Hey,
Whenever I open up my task manager (when there's no progams on) the cpu usage does little "jumps" from time to time. Every second or so, the cpu usage goes to around 20-30% then drops to zero, a second later it goes back up again and it goes in a cycle. This started only a few days ago and I've had my laptop for around a year now. I downloaded Process Explorer and found out that hardware interrupts were taking up most of my cpu usage, around 20-40% if i'm running anything or not. It affects the cursor, sound and stuff like opening windows and stuff. Its a Windows XP SP2 with an Intel Pentium M processor. Help!

When was the last time you updated all of your drivers?

Also, have you considered a BIOS upgrade for your system?

Only my display driver (ATI mobility radeon 9600 pro turbo)
and i've done a bios upgrade as well (dell inspiron 8600 A14)

Sry, The edit button dissapeared...
A week ago, but i did a roll back because it kinda made the stuff on my screen smaller. (toaskbar, icons, etc.)