Wow. That is sincerely disappointing.
I have honestly never heard of such problems before, and my Pro works like a dream.
If you have an Apple store near you, you could make an appointment to see if someone could at least diagnose the problem. I know you said it is out of warranty, but the genius bar or whatever they call themselves now should still take a look at it for free.
Somebody mentioned a toast harddrive... If that is the case harddrives are relatively inexpensive, depending on how much storage you want. However, getting them installed is something that people seriously overcharge. If at all possible I'd try to do that yourself, or find someone you know to do it for you. The only think you may risk is voiding your warranty, but since yours is already out of warranty...
Please keep in mind that I am not a computer genius by any means... I'm just married to one. LOL! I get a lot of my "knowledge" by watching him play family tech support.