create following store procedure
 
CREATE  PROCEDURE [InsertRegistration] @fname VARCHAR(50),@lname VARCHAR(50),
@uname VARCHAR(50),@passwo VARCHAR(50),@repasswo VARCHAR(50),@email VARCHAR(50),
@contact VARCHAR(50),@gender VARCHAR(50)ASBEGIN	INSERT INTO regis 	(		fname ,
		lname ,		uname ,		passwo ,		repasswo,		email,		contact ,		gender ,		email 		)
	VALUES	(		@fname,		@lname,		@uname ,		@passwo ,		@repasswo ,		@email ,
		@contact ,		@gender,		@email 		)		INSERT INTO details	(		contact,		email	)
	VALUES	(		@contact ,		@email	)END
to call Store Procedure refer :http://www.aspsnippets.com/Articles/Calling-Insert-SQL-Server-Stored-Procedures-using-ADO.Net.aspx