HELP: Premire Pro Makes My Computer Run SUPER SLOW!!!!

I bought a computer about three months ago just for the use of video editing. The computer is an HP, it has a 2.4 Quad Core CPU, 8 gigs of ram and a Nivida GeForce 8500 GT graphics card, and two 500 Gig Hard Drives. I bought Adobe CS3 Productions Suite to do all of my editing with. When I installed the software on my computer I could use it sometimes for days and sometimes for weeks doing some editing and then it would just hit a brick wall and completley loose all of its performance. I dont mean it would drop a little bit, I mean it would get to the performance and speed ratings of a computer that you would have owned ten years ago. I had performed about 5 system recoverys before I became so frustrated and fed up with the issue that I was desperate! I came to learn that 64-Bit vista is not compatible with Premiere Pro CS3. So then I was told to solve my issue I could partition my drives to run a dual boot. One partition would boot 64-Bit Vista the other would boot 32-Bit Vista to solve the compatibility issue. Everything was going smooth until today when it hit a brick wall just like my previous issue!!! I am so frustrated right now if anyone could help I would be appualed, so please any suggestions would do!

Thanks for your help!