My system:
Ubuntu 9.10/gnome

Gateway SX2802 with Intel Q8300, 4GB ram, 750GB drive only 6 months old.

PROBLEM
My internal drive is read/writing continuously without stopping no matter what I am doing.
It begins immediately after boot. It simply runs and runs nonstop. This is with NO APPLICATIONS running.
This is a problem which cropped up suddenly after 5 months of running just fine.

What I have tried:
1. Disconnecting Internet - no change
2. Looking at processes in System Monitor. Well, everything says "sleeping" and there isn't anything that looks obvious to me, but there are a LOT of processes.

I am afraid my drive will simply burn up.

Doubt if this is it but the same happened to me when I installed mythtv once. Just uninstalled it and subsequently installed a slightly different version.

Nope, I don't have mythTV installed. Not that.
I just tried opening System Monitor and killing processes one by one. The system died before I got to one that stopped the disk activity.

This was never resolved on 9.10 Ubuntu. I upgraded to 10.04 and that seems to have fixed it.