My 10.4.1 "Crash" Issue

Hi all.. I'm a new Mac user and have become very discouraged by an issue I've been having. Here's how it started:

Everything was going fine until I installed Fugu. I installed the most recent version, but I'm not sure that it was Tiger compatible. After I installed this, whenever I would leave my computer idle for random times, I would be "logged out" and greeted by the Keyboard Setup Assistant (I have a non-apple keyboard that I have to initialize). The biggest problem with this is that it completely logs me out and I lose ALL of my temporary data (IMs are the most crucial thing here) as well as whatever I had open at the time.

I dragged Fugu to the trash and the problems seemed to go away. From that point onwards, I only installed software that I know for sure is compatible with Tiger. However, a few days ago, it randomly started happening again. I uninstalled everything that I had installed since the last time the computer was working fine (which, by the way, is amazingly annoying as I currently have TWO pieces of software - Adium and World of Warcraft - that didn't originally come with the computer) but it hasn't solved a thing. The computer still randomly logs me out and loses all information regarding my keyboard.

This will happen at random times, usually about 30 to 40 minutes into an idle, after my screen saver and SCREEN power saver have begun. It's very odd.

Please help, if you can, or let me know what else I can post here that might help diagnose the problem.

Thanks!