QUIT taking it to the Geeks....find a different repairman. My best friend was doing like you -- taking one back to the same place over and over and over again. ALWAYS was her fault. I convinced her to go to a different place. The computer got fixed and no more problems.
In answer to your question --- NO, that's never happened to me. If you have a good virus/spamware program and you're not in deleting program stuff, you shouldn't have these problems. Obviously the place you're taking it to isn't fixing it --- but they're getting money out of you.
and BTW -- you can reformat your computer FOR FREE! The installation disks you get with the computer will do that....research on the internet and learn how to do it!!!!