My children have non-administrator accounts on their computers, one of which uses Windows XP. Maybe that doesn't encourage them to learn, but that's how it is at the moment. They wanted to install (again) I Spy Fantasy, an old game, but it required administrative access. That was ok. But then we found that administrative access was required not just to install, but also to play the game. That's not ok.
A short web search didn't yield any answers, so I delved. The error message reported that it couldn't save game details to the disk. Probably because it stores the saved games in C:\Program Files\Scholastic...
I tried to move the saved games folder, and make a shortcut, but that seemed fruitless. So I moved the whole installation folder from Program Files to daughter's Documents and Settings folder. But when running the application, it still complained about the same problem. I wondered if the registry was pointing to the old location. Sure enough - Local Computer/Software/Scholastic inc/I Spy Fantasy/install-dir pointed to Program Files... . So I changed that, switched users back to the non-administrative account, and tried again. This time, the error message was new: the program was trying to modify the registry! Well, it looks like in regedit, you can set permissions for different entries. So I gave the non-privileged user full control for just the I Spy Fantasy folder. That's better.
Oops. One last problem. Don't forget to adjust where the start menu shortcut points to!
That seems to have solved the problem. I wonder if anyone else cares about such things. Maybe you'll leave me a comment if this helps.