Basically, my PC's HD is being accessed all the damn time even when nothing is supposed to be going on. By what or for what, I don't know. What I do know is it's annoying. Is there any way I can see which programs are doing this?
Yep, Process Explorer is a powerful tool and this is one of the things it lets you do. Download it, run it then right click on the display header and click on "Select Columns". Then click on the "Process Performance" tab and check the "I/O Reads" and "I/O Writes" boxes. Then look for the process whose I/O Reads or I/O Writes is increasing. That will probably be what's accessing your HDD.
Yes, I'm using Vista. I didn't know of the Res Mon in Task Manager so I didn' t even look Ironically I have both of the Sysinternals tools on a CD somewhere, but I didn't think they'd show disk access.