19 to 22 is about what a standard installation of XP is with some of the more blatant services shut down. Not optimal, but not killer either.
If you are surging that high on CPU usage, you definately have some programs eating up resources, and like Star said, spyware/malware if the first thing to check for.
They normally do not show up in the task manager, but some do. See if you have many 'run32dll.exe' processes. This is a clue you have some spyware running in the background.