MacBook Pro automatically logging me off

So recently my MacBook Pro has been randomly logging me off for no reason. I took it to the apple store and they said it had something to do with the Adobe applications. They uninstalled and re installed them and it worked fine for about a week. Then it started doing it again. So I uninstalled them again and never reloaded them. And just tonight it started doing it again with NO Adobe products/services loaded at all. I have noticed that it only logs me off when I try to open the Applications button at the bottom or if I try to open/start my Dashboard. WTF is going on?!?!?! I am a student so I can't really afford to pay Apple to have it fixed and it is out of warranty.

Some specs:
Mac OS X Version 10.6.8
Processor 2.4 GHz Intel Core 2 Duo
Memory 4 GB 1067 MHz DDR3

Please any help would be appreciated. I am really sick of this. If there is another thread that has already answered this question just point me in the right direction. Sorry if I posted this in the wrong section. Just move it if need be.

Oh and the automatic logoff option in preferences is NOT on. That is the first thing I checked, so PLEASE do not suggest I try that.

Thanks guys!