How about instead of using a MsgBox for the Password Invalid line, use an InputBox and have the user put their next attempt at the password in through that?
I think you would use something like
Password = Inputbox(“Password Invalid. Type password here:”)
Then what they type into the InputBox would become the new value of the Password string.
By the way, I think the loop from 0 to 3 will let the user have 4 attempts, instead of 3.