I have added the validation group also you have not added the style in some tags properly.
I would suggest you to do Control + K + D to format the code.
HTML
<form id="form1" runat="server">
<div>
<table align="center" border="0" cellpadding="0" cellspacing="0" width="700">
<tr>
<td align="center" class="formHeading">
Add a New User
</td>
</tr>
<tr>
<td align="center" style="height: 20px">
</td>
</tr>
<tr>
<td align="left" style="height: 20px" class="nbdcontent">
</td>
</tr>
<tr>
<td align="center" style="height: 20px">
</td>
</tr>
<tr>
<td>
<table border="0" cellpadding="0" cellspacing="0" width="700">
<tr style="color: #000000">
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 9px; height: 17px;">
</td>
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 141px; height: 17px;"
valign="top">
</td>
<td align="left" class="nbdcontent" style="height: 17px" valign="top" colspan="5">
<asp:Label ID="lblMsg" runat="server" Font-Bold="True" Visible="False"></asp:Label>
</td>
<td align="left" style="height: 17px;" valign="top">
</td>
<td style="width: 100px; height: 17px;">
</td>
</tr>
<tr style="color: #000000">
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 9px; height: 17px;">
</td>
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 141px; height: 17px;"
valign="top">
</td>
<td align="left" class="nbdcontent" style="height: 17px" valign="top" colspan="5">
</td>
<td align="left" style="height: 17px;" valign="top">
</td>
<td style="width: 100px; height: 17px;">
</td>
</tr>
<tr style="color: #000000">
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 9px; height: 17px;">
</td>
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 141px; height: 17px;"
valign="top">
</td>
<td align="left" class="nbdcontent" style="height: 17px" valign="top" colspan="5">
<asp:RadioButtonList ID="RadioButtonList1" runat="server" CssClass="nbdcontent" AutoPostBack="True"
RepeatDirection="Horizontal" Font-Bold="True" Font-Size="Medium">
<asp:ListItem Value="0">CPMU</asp:ListItem>
<asp:ListItem Value="1">SPMU</asp:ListItem>
<asp:ListItem Value="2">SFTI</asp:ListItem>
</asp:RadioButtonList>
</td>
<td align="left" style="height: 17px;" valign="top" colspan="2">
<asp:RequiredFieldValidator ID="RequiredFieldValidator5" runat="server" ValidationGroup="Group1"
ControlToValidate="RadioButtonList1" ErrorMessage="Type required !">*</asp:RequiredFieldValidator>
</td>
</tr>
<tr style="color: #000000">
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 9px; height: 17px;">
</td>
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 141px; height: 17px;"
valign="top">
</td>
<td align="center" class="nbdcontent" style="height: 17px" valign="top">
</td>
<td align="left" style="width: 120px; height: 17px;" valign="top">
</td>
<td align="left" style="width: 120px; height: 17px;" valign="top">
</td>
<td nowrap="nowrap" style="height: 17px;" align="left" class="nbdcontent" valign="top">
</td>
<td align="center" class="nbdcontent" style="width: 13px; height: 17px" valign="top">
</td>
<td align="left" style="height: 17px;" valign="top">
</td>
<td style="width: 100px; height: 17px;">
</td>
</tr>
<tr style="color: #000000">
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 9px; height: 17px;">
</td>
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 141px; height: 17px;"
valign="top">
State
</td>
<td align="center" class="nbdcontent" style="height: 17px" valign="top">
:
</td>
<td align="left" style="width: 120px; height: 17px;" valign="top">
<asp:DropDownList ID="ddlStates" runat="server" AutoPostBack="True" CssClass="mytextbox"
AppendDataBoundItems="True" DataTextField="State" DataValueField="State_Id" Enabled="False">
<asp:ListItem Value="0">-Select-</asp:ListItem>
</asp:DropDownList>
</td>
<td align="left" style="width: 120px; height: 17px;" valign="top">
</td>
<td nowrap="nowrap" style="height: 17px;" align="left" class="nbdcontent" valign="top">
</td>
<td align="center" class="nbdcontent" style="width: 13px; height: 17px" valign="top">
</td>
<td align="left" style="height: 17px;" valign="top">
</td>
<td style="width: 100px; height: 17px;">
</td>
</tr>
<tr style="color: #000000">
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 9px; height: 17px;">
</td>
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 141px; height: 17px;"
valign="top">
</td>
<td align="center" class="nbdcontent" style="height: 17px" valign="top">
</td>
<td align="left" style="width: 120px; height: 17px;" valign="top">
</td>
<td align="left" style="width: 120px; height: 17px;" valign="top">
</td>
<td nowrap="nowrap" style="height: 17px;" align="left" class="nbdcontent" valign="top">
</td>
<td align="center" class="nbdcontent" style="width: 13px; height: 17px" valign="top">
</td>
<td align="left" style="height: 17px;" valign="top">
</td>
<td style="width: 100px; height: 17px;">
</td>
</tr>
<tr style="color: #000000">
<td align="right" class="nbdcontent" style="width: 9px; height: 17px">
</td>
<td align="left" class="nbdcontent" style="width: 141px; height: 17px" valign="top">
SFTI
</td>
<td align="center" class="nbdcontent" style="height: 17px" valign="top">
:
</td>
<td align="left" colspan="2" style="width: 120px; height: 17px" valign="top">
<asp:DropDownList ID="ddlSFTI" runat="server" AutoPostBack="True" CssClass="mytextbox"
DataTextField="SFTI_Name" DataValueField="SFTI_Id" Enabled="False">
<asp:ListItem Value="0">-Select-</asp:ListItem>
</asp:DropDownList>
</td>
<td align="left" class="nbdcontent" style="height: 17px" valign="top">
</td>
<td align="center" class="nbdcontent" style="width: 13px; height: 17px" valign="top">
</td>
<td style="width: 100px; height: 17px" valign="top">
</td>
<td style="width: 100px; height: 17px">
</td>
</tr>
<tr style="color: #000000">
<td align="right" class="nbdcontent" style="width: 9px; height: 17px">
</td>
<td align="right" class="nbdcontent" style="width: 141px; height: 17px" valign="top">
</td>
<td align="center" class="nbdcontent" style="height: 17px" valign="top">
</td>
<td align="left" colspan="2" style="width: 120px; height: 17px" valign="top">
<asp:Label ID="lblUserId" runat="server" Visible="False"></asp:Label>
</td>
<td align="left" class="nbdcontent" style="height: 17px" valign="top">
</td>
<td align="center" class="nbdcontent" style="width: 13px; height: 17px" valign="top">
</td>
<td style="width: 100px; height: 17px" valign="top">
</td>
<td style="width: 100px; height: 17px">
</td>
</tr>
<tr style="color: #000000">
<td align="right" class="nbdcontent" style="width: 9px; height: 17px">
</td>
<td align="left" class="nbdcontent" style="width: 141px; height: 17px" valign="top">
User Id
</td>
<td align="center" class="nbdcontent" style="height: 17px" valign="top">
:
</td>
<td align="left" colspan="2" style="width: 120px; height: 17px" valign="top">
<asp:TextBox ID="txtUserId" runat="server" CssClass="mytextbox" AutoPostBack="True"></asp:TextBox>
</td>
<td align="left" class="nbdcontent" style="height: 17px" valign="top">
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ValidationGroup="Group1"
ControlToValidate="txtUserId" ErrorMessage="User Id Required !">*</asp:RequiredFieldValidator>
</td>
<td align="center" class="nbdcontent" style="width: 13px; height: 17px" valign="top">
</td>
<td style="width: 100px; height: 17px" valign="top">
</td>
<td style="width: 100px; height: 17px">
</td>
</tr>
<tr style="color: #000000">
<td align="right" class="nbdcontent" style="width: 9px; height: 17px">
</td>
<td align="left" class="nbdcontent" style="width: 141px; height: 17px" valign="top">
</td>
<td align="center" class="nbdcontent" style="height: 17px" valign="top">
</td>
<td align="left" colspan="2" style="width: 120px; height: 17px" valign="top">
</td>
<td align="left" class="nbdcontent" style="height: 17px" valign="top">
</td>
<td align="center" class="nbdcontent" style="width: 13px; height: 17px" valign="top">
</td>
<td style="width: 100px; height: 17px" valign="top">
</td>
<td style="width: 100px; height: 17px">
</td>
</tr>
<tr style="color: #000000">
<td align="right" class="nbdcontent" style="width: 9px; height: 17px">
</td>
<td align="left" class="nbdcontent" style="width: 141px; height: 17px" valign="top">
Email
</td>
<td align="center" class="nbdcontent" style="height: 17px" valign="top">
:
</td>
<td align="left" colspan="2" style="width: 120px; height: 17px" valign="top">
<asp:TextBox ID="txtEmail" runat="server" CssClass="mytextbox"></asp:TextBox>
</td>
<td align="left" class="nbdcontent" style="height: 17px" valign="top">
<asp:RegularExpressionValidator ID="RegularExpressionValidator1" ValidationGroup="Group1"
runat="server" ControlToValidate="txtEmail" ErrorMessage="Email is not valid !"
ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*">*</asp:RegularExpressionValidator>
</td>
<td align="center" class="nbdcontent" style="width: 13px; height: 17px" valign="top">
</td>
<td style="width: 100px; height: 17px" valign="top">
<asp:RequiredFieldValidator ID="RequiredFieldValidator4" ValidationGroup="Group1"
runat="server" ControlToValidate="txtEmail" ErrorMessage="Email required !">*</asp:RequiredFieldValidator>
</td>
<td style="width: 100px; height: 17px">
</td>
</tr>
<tr style="color: #000000">
<td align="right" class="nbdcontent" style="width: 9px; height: 17px">
</td>
<td align="right" class="nbdcontent" style="width: 141px; height: 17px" valign="top">
</td>
<td align="center" class="nbdcontent" style="height: 17px" valign="top">
</td>
<td align="left" colspan="6" style="height: 17px" valign="top">
<asp:RegularExpressionValidator ID="Regex2" runat="server" ValidationGroup="Group1"
ControlToValidate="txtpassword" ValidationExpression="^(?=.*[A-Za-z])(?=.*\d)(?=.*[$@$!%*#?&])[A-Za-z\d$@$!%*#?&]{8,}$"
ErrorMessage="Minimum 8 characters atleast 1 Alphabet, 1 Number and 1 Special Character"
ForeColor="Red" Display="Dynamic" />
</td>
</tr>
<tr style="color: #000000">
<td align="right" class="nbdcontent" style="width: 9px; height: 17px">
</td>
<td align="left" class="nbdcontent" style="width: 141px; height: 17px" valign="top">
Password
</td>
<td align="center" class="nbdcontent" style="height: 17px" valign="top">
:
</td>
<td align="left" colspan="2" style="width: 120px; height: 17px" valign="top">
<asp:TextBox ID="txtpassword" runat="server" CssClass="mytextbox" TextMode="Password"
onchange="ToggleButton();"></asp:TextBox>
</td>
<td align="left" class="nbdcontent" style="height: 17px" valign="top">
<asp:RequiredFieldValidator ID="RequiredFieldValidator2" ValidationGroup="Group1"
runat="server" ControlToValidate="txtpassword" ErrorMessage="Password Required !">*</asp:RequiredFieldValidator>
</td>
<td align="center" class="nbdcontent" style="width: 13px; height: 17px" valign="top">
</td>
<td style="width: 100px; height: 17px" valign="top">
</td>
<td style="width: 100px; height: 17px">
</td>
</tr>
<tr style="color: #000000">
<td align="right" class="nbdcontent" style="width: 9px; height: 17px">
</td>
<td align="left" class="nbdcontent" style="width: 141px; height: 17px" valign="top">
</td>
<td align="center" class="nbdcontent" style="height: 17px" valign="top">
</td>
<td align="left" colspan="6" style="height: 17px" valign="top">
<asp:CompareValidator ID="CompareValidator1" runat="server" ValidationGroup="Group1"
ControlToCompare="txtpassword" ControlToValidate="txtConfirmpassword" ErrorMessage="Confirmed Password did not match"></asp:CompareValidator>
</td>
</tr>
<tr style="color: #000000">
<td align="right" class="nbdcontent" style="width: 9px; height: 17px">
</td>
<td align="left" class="nbdcontent" style="width: 141px; height: 17px" valign="top">
Password Confirmed
</td>
<td align="center" class="nbdcontent" style="height: 17px" valign="top">
:
</td>
<td align="left" colspan="2" style="width: 120px; height: 17px" valign="top">
<asp:TextBox ID="txtConfirmpassword" runat="server" CssClass="mytextbox" TextMode="Password"
onchange="ToggleButton();"></asp:TextBox>
</td>
<td align="left" class="nbdcontent" style="height: 17px" valign="top">
<asp:RequiredFieldValidator ID="RequiredFieldValidator3" ValidationGroup="Group1"
runat="server" ControlToValidate="txtConfirmpassword" ErrorMessage="Confirmed Password Required !">*</asp:RequiredFieldValidator>
</td>
<td align="center" class="nbdcontent" style="width: 13px; height: 17px" valign="top">
</td>
<td style="width: 100px; height: 17px" valign="top">
</td>
<td style="width: 100px; height: 17px">
</td>
</tr>
<tr style="color: #000000">
<td align="right" class="nbdcontent" style="width: 9px; height: 17px">
</td>
<td align="right" class="nbdcontent" style="width: 141px; height: 17px" valign="top">
</td>
<td align="center" class="nbdcontent" style="height: 17px" valign="top">
</td>
<td align="left" colspan="2" style="width: 120px; height: 17px" valign="top">
<asp:Button ID="Button1" runat="server" Text="Submit" ValidationGroup="Group1" />
</td>
<td align="left" class="nbdcontent" style="height: 17px" valign="top">
</td>
<td align="center" class="nbdcontent" style="width: 13px; height: 17px" valign="top">
</td>
<td style="width: 100px; height: 17px" valign="top">
</td>
<td style="width: 100px; height: 17px">
</td>
</tr>
<tr>
<td style="width: 9px; height: 19px;" class="nbdcontent">
</td>
<td style="width: 141px; height: 19px;" class="nbdcontent" valign="top">
</td>
<td style="height: 19px;" align="center" class="nbdcontent" valign="top">
</td>
<td style="height: 19px;" valign="top" colspan="6">
<asp:RegularExpressionValidator ID="Regex3" runat="server" ControlToValidate="txtConfirmpassword"
ValidationExpression="^(?=.*[A-Za-z])(?=.*\d)(?=.*[$@$!%*#?&])[A-Za-z\d$@$!%*#?&]{8,}$"
ErrorMessage="Minimum 8 characters atleast 1 Alphabet, 1 Number and 1 Special Character"
ForeColor="Red" Display="Dynamic" />
</td>
</tr>
<tr style="color: #7f6a63">
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 9px; height: 18px"
valign="top">
</td>
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 141px; height: 18px"
valign="top">
</td>
<td align="center" class="nbdcontent" style="height: 18px" valign="top">
</td>
<td align="left" style="height: 18px" valign="top">
</td>
<td align="left" style="height: 18px" valign="top">
</td>
<td align="left" class="nbdcontent" nowrap="nowrap" style="height: 18px" valign="top">
</td>
<td align="center" class="nbdcontent" style="width: 13px; height: 18px" valign="top">
</td>
<td align="left" valign="top" style="height: 18px">
</td>
<td style="width: 100px; height: 18px">
</td>
</tr>
<tr style="color: #7f6a63">
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 9px; height: 18px"
valign="top">
</td>
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 141px; height: 18px"
valign="top">
</td>
<td align="center" class="nbdcontent" style="height: 18px" valign="top">
</td>
<td align="left" style="height: 18px" valign="top">
</td>
<td align="left" style="height: 18px" valign="top">
</td>
<td align="left" class="nbdcontent" nowrap="nowrap" style="height: 18px" valign="top">
</td>
<td align="center" class="nbdcontent" style="width: 13px; height: 18px" valign="top">
</td>
<td align="left" valign="top" style="height: 18px">
</td>
<td style="width: 100px; height: 18px">
</td>
</tr>
<tr style="color: #7f6a63">
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 9px; height: 18px"
valign="top">
</td>
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 141px; height: 18px"
valign="top">
</td>
<td align="center" class="nbdcontent" style="height: 18px" valign="top">
</td>
<td align="left" valign="top" colspan="6" rowspan="2">
<asp:ValidationSummary ID="ValidationSummary1" runat="server" ValidationGroup="Group1"
ShowMessageBox="true" ShowSummary="false" />
</td>
</tr>
<tr style="color: #7f6a63">
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 9px; height: 18px"
valign="top">
</td>
<td align="left" class="nbdcontent" nowrap="nowrap" style="width: 141px; height: 18px"
valign="top">
</td>
<td align="center" class="nbdcontent" style="height: 18px" valign="top">
</td>
</tr>
</table>
</td>
</tr>
</table>
</div>
</form>
Screenshot
