VERY slow system

I have a Celeron 1700 with 1 GB RAM and I am always getting locked up. I will hit CTRL - ALT - Del and the CPU % runs from 100 % for 1 -2 minutes, then drops to 16 - 20 % and then will climb right back up to 100% after 10 minutes. The fan on the back of the system will start when the CPU speed increases and it funs full blast, then stops. I have run antivirus (Norton) and spyware as well as defrag and scan disk and nothing. Anything else I can check?

 

I should also mention, I am running Win XP Home SP2. Tasks running are MS Money, Printer software, Linksys, Intel Extreme Graphics, Quicktime, Norton

 

Do you have Norton Speed Disc? Almost as big a hog as indexing. To stop you must disable the Speed Disc Service: Admin. Tools>Services>Rt. click and change from drop-down menu>Apply. Go back and turn it on if you want to run Speed Disc.
If you have recently upgraded to IE7 you probably have ctfmon.exe running. Not necessary for ordinary users who don't need to switch text languages. To turn it off: Control Panel>Reg.&Lang. Options>Languages>Detail>Advanced. Check the box "Turn off advanced text services." Reboot.
Sysinternals Process Explorer is very helpful: http://www.microsoft.com/technet/sysinternals/ProcessesAndThreads/ProcessExplorer.mspx (Download link at bottom of page) No installation, just run from saved location.
You did not give full details about your malware protection. Experts use several different scanners/removal tool to make sure. No program catches everything. Frankly, most of your type of problem turn out to be malware of some kind. Take steps to be sure! Strongly suggest you go to following link and follow the whole procedure: http://forums.majorgeeks.com/showthread.php?t=35407