That is strange! Maybe it will work if you create a fresh user account... I found this, someone with the same problem:
http://www.mcse.ms/archive210-2004-9-1075355.html
Quote:
1. Click Start / Control Panel / User Accounts / Create a New Account /
Name the Account: "able2play" (without quotes) / Next Pick: "Computer-
Administrator" & Click "Create Account";
2. Click on your new able2play account and Create a Password for it;
3. When your limited user wants to play a game that requires Administrator
privileges they can Right-Click the shortcut to that game / Click Run As... /
"The Following User": able2play and enter the password. Simple as that!
Hope that helps, if not i'm stumped
