process is the only process running which takes 99% of the CPU? In fact, normally the system shall be idle after computer start up and the system idle process will take 99% of CPU when nothing is running. But my situation is just opposite which causes my computer almost not functioning. If I terminate the system process, my computer will be shut down right away. My anti-virus and spyware programs did not detect anything. What might be the causes? Any suggestions to fix this situation? My system is AMD Athlon 3200 running with Win XP Prof.Thanks for any input fixing this problem...This is what I have done so far, I restored my system to a point earlier than the time when this problem was occurred, but no cure. By the way, when this system process is in 100%CPU, there is no other things running and my computer has more than 700 Meg available out of my I GB memory. So definitely, this is not a memory problem.So if this is caused by some driver corruption, or out-dated, what might be the best way to locate this troubled drive? I did not find any yellow tag or red tag when I browse the the list in the device manager.Any suggestions?

well for one thing ... what type of programs are you running and when is your system looking for updates (cookies. xp upgrades, other programs). you might not have viruses or maleware running.. but if you have programs looking for updates that can take a lot of system resources

I use to have that problem, and it turned out to be my network driver (i think), so you should try to update as many drives as you can.BUT IT IS CAUSED BY A DRIVER, IT TOOK ME 4 DAY TO FIND OUT WHICH ONE THOUGH.

excess cpu usage can occure when a program is closed out of before it loads completely. if you get tired of waiting and x out that leaves an opening for memory leaks. Add more ram too, i was using 100% added another 256mb of ram and now use 2-10% cpu. Do a disk clean up and a defrag session. dfrag the drive several times too not just once. usually (C drive.