I just read the first post of this thread and have no time to read all the other posts, maybe some have already mentioned it, but from what you've said I beleive you have a virus on your system if cpu is at 100% and you cannot determine a geniune application is using it.
I also saw couple of lines of Norton/Mcfee breezing through the posts. I recommend niether. they're not great and slow your computer down.
I highly recommend Nod32. I use it, and it's the best anti-virus there is in my view. it is extremely small and does not slow your computer at all. I'ved used others and in my view it is the best.
I just checked the 2 snapshots uve put up in the previous post. I don't see any problem there. all processes are normal and i don't see the cpu running at 100%.
if it only spikes to 100%, then that is perfectly normal. if it remains above 80% consistantly to the point that it freezes your computer (esp. when charting software is off) then you certainly have a virus. but I can't see anything suspecious in ur processes.