My harddisk usage spikes in 1 minute cycles...seriously.

I have never seen nor can find any info on anything like this. Every minute, on the dot, my hard disk usage spikes to 100%. (CPU stays normal) I have ran every virus, trojan, malware, and worm scanner possible, and decided it can't be anything else but the disk itself. Unless anyone has any clue as to why this would happen, I fear I may have to buy a new disk. Also, the same thing happens when I try to open add/remove programs, only it happens constantly until I close the blank window. It's really bugging me because I have an amateur recording studio running pro-tools and every minute (ON THE DOT) I get a playback error because of this problem. It happens when I have no programs running. Any suggestions?