Hello Sean. Firstly, a very important suggestion to you.
Never rename any system files or their extensions unless absolutely necessary. Renaming a system file might make your computer act awry or even make it unbootable.
Now, whenever you start in
Safe Mode, most of the drivers are not loaded. This is done so that you may identify driver conflicts if there are any. Its not unusual to see a
Safe Mode boot with low colour depth but it is not usual too. As I said above, restore the file you modified. Its alright as long as the extension is same as capitalization generally doesn't matter. Just restore it and try again in
Safe Mode to see if you have a higher colour depth. Also, it is not unusual to experience problems with such high resolutions and unfortunately, there is no patch to correct this as the games weren't probably made for such high resolutions. For this, I recommend that you lower your resolution if you want to play the game in full screen mode or live with the Windowed mode. I know I am being a little unhelpful but it is all for your own good. Please try and understand that it is not important to play it in such high resolutions with full screen mode. Besides, you may find the Windowed mode convenient in some form. That is all I have to say. Good Luck.
-- Goku