Freezing after reinstalling Windows 7 x64 bit

My problem began to occur after reinstalling windows 7 x64 bit. I tried updating drivers, cleaning registry, increasing fan speed, dusting my hardware, but nothing worked. The freezing sort of drifted away and randomly stopped occuring. A few months later, my sister influenced me to downgrade to windows xp. the installation failed, so I had to reinstall windows again. The freezing started up again. Its been a good two months now, and I cannot stop the freezing. I've done all of the above and tried several different programs to clean my registry, increase fan speeds, and update drivers. I uninstalled sp1 because it seemed to make the freezing even worse. I also get about one blue screen every day. Freezing occurs mostly every 10-30 minutes, sometimes even right after booting my pc. the mouse wont move, the keyboard lights wont change when i hit caps lock, and sometimes a strange buzzing noise comes from my speakers.

Please help me with this problem! I'm an intense gamer and this totally blows!
-Marcus

Alot of so-cslled Registry Cleaner's mess up your pc. It could also be a BIOS issue. Try checking the company that make's your motherboard's web site for a BIOS update. Download CPU-z from wwww.cpuid.com and search through the Mainboard tab on the top. That list's who make's your motherboard, it's model number and the version of it's BIOS that's currently installed. Also look at the Memory tab in CPU-z and write down those figure's. That is the current RAM Timings the BIOS is using. Now click on the SPD tab in CPU-Z those are the timing's your ram support's. Compare those with the one's you wrote down. If they're different from what CPU-z's SPD tab says, change that in the BIOS.