i m not able to store and retrieve the data in sqlserver

Question

i have made a registration form using bootstrap in asp.net with all its required validation.

Now ,i m not able to store it in sqlserver.

 

 

i also need one more help.

i have one table for registration with following fields

name ,lastname,username,email address......

Now,i have another form ....where i want the user to enter his username and i want his mail address to be automatically generated in email textbox