Oh dear. That is NOT the way to delete games. You must go through the remove program in control panel.
You need to remove the game from your computers registry - thats where it still thinks the game is around. If you dont know what you are doing, I suggest you download some free software. Get Reg Cleaner from http://www.downloads.com
and follow the instructions.
Always create a system restore point before doing such a task. Then, reboot and re-install the game