We have four so that we can't go outside any part of the form, to prevent any cheating. But this time, when we hit the border it will move the player back by the value it is trying to move forward so we can't get past the border!
and that's it, You have a working game 
Here is the full program listing, Remeber I put my timer in using the designer mode, not in code so make sure you either make a coded one or implement one from the designer.