You can't run Puzzle Quest on Windows 7? Do you see black screen, or compatibility error? If you want to repair that, just follow this steps:

1. Go to folder where your game is installed. Default:

C:\Program Files (x86)\Steam\SteamApps\common\Puzzle Quest

2. Use right mouse button on Puzzle Quest.exe file and select Properties.
3. Go to Compatibility page and select Run this programm as administrator.
4. You can select Windows XP compatiblity mode too.

Here it is. Now you can run your game and enjoy it. Thanks for reading.