System pause problem

AMD Athlon 2400+
Asus A7N8X standard version
512 CL2 Corsair PC2700 (DDR mode)
GeForce 4 Ti4200
Windows XP Professional

I am extremely confused. I have had my system for a while now and have never had a problem.

Just recently my entire system pauses every few seconds for maybe a quarter of a second, but it pulses and halts. It seems to happen randomly when I access any files or run any programs. It will even do it in games, usually when I load a saved game but it never lasts long. I thought it might have to do with my hard drive, seeing as it's really old and my D partition has crashed due to gaming so many times that it is constantly checked for consistency, although it passes each time. Also C is NTFS and D FAT32 that's ok right?

The only thing I can think of is I set my upload user limit on Kazaa to 10 for the first time and let about 10 people download off me while I slept all night. I think the problem started then because my computer was running really choppy and slow from so much intense uploading (I have a cable modem) and if i'm correct it started right after that. I didn't damage my RAM did I? It's high quality gaming Corsair RAM with thick heat spreaders. Can this be a sign of CPU overheating? I have plenty of cooling (4 case fans and a factory CPU fan/heatsink). Maybe a virus or trojan of some sort? I'm completely stumped, this is a such a fast system it's annoying.

Badassjedi