I'll request some information too.
What's your current operating system?
The system idle process thing is normal. The CPU can't just stop doing anything, so it creates a process to keep itself occupied. Its usage varies depending on how much 'idle' processing capacity your processor has available. This process itself doesn't have much of any load associated with it, though.
Anything sticking out in the task manager besides the idle process, in regards to reported usage?
I am running XP home Edition SP3, AMD Sempron 3400+, the only process that sticks out is hpsysdrv.exe