BleepingComputer.com: hal.dll causing BSoD/freeze

Hey guys! I've been having a lot of BSoDs and complete computer freezes over the past few months. They usually happen while I'm playing graphic-intensive games such as World of Warcraft and Witcher, but a BSoD just happened about 20 minutes ago while my computer was deleting a temp file (No games running).
When they first began, I thought it was because of my graphics card. I bought a GeForce 9500GT card, installed the latest drivers, and they kept happening. I downloaded the BlueScreenView program, and that's telling me that the problem is being caused by the file hal.dll. I've googled the problem and have found absolutely no help. I called up my computer manufacturer and the guy told me that the problem wasn't hal.dll, but it was because of the amount of storage left in my HD, and that he'd clear up the problem for $49.99. I said no, because I knew it was BS and they were just trying to get money out of me.
Do you guys think I should try to reinstall my OS? If so, how? I don't have any of the original discs or key codes, they all burned up in a house fire a few years back. If I shouldn't reinstall the OS, how can I fix the hal.dll problem?