Log in process using entity framework asp.net mvc

Log in process using entity framework asp.net mvc

I want to have log in password verification in my project.when user clicks
on the log in button compiler goes to this method
public ActionResult VerifyPassword(User user)
{
var givenPassword =user.Password;
var givenUserName=user.UserName;
//now i need compare password
var myUser=db.User.Find(somevalue)//find user from database,But how can i
do this????Because somevalue needs to be a Primary Key
}
If i am doing something wrong.Please point me into right direction I
searched a lot on the Web.But no tutorial was found to accomplish this
using entity framework.