I'm sure that this topic doesn't belong here since this is a codec help forum, but I do have something to say that might help.
I don't have much informaion to help trouble shoot this problem.
There are alot of things that could max out your system.
If you are compleatly sure that you aren't knowing running anything that would take up that much of the computer resourses, than you have to answer a few questions.
1. How up todate is your anti-virus program and when was the last time it did a full scan of the computer?
2. Do you have an anti-spyware/adware blocker? When was the last time you ran it an got a clean bill of health?
3. Do you know what defraging is? If you have had the computer for over year and you haven't done it, and you watch movies, and all out use the computer for anything other than just reading a story or two for over 5 hours a day, you may need to defrag your hard drive. It will slow down your computer, but I've never had it so bad that it maxes our your cpu. Infact I don't think it could, but it's something that should be done on a bases that matches how much you use your computer and for what you use it for.
4. I take it you have an xp computer. You will have programs called services. Now unless you are connect to a network and do a few other things with your computer you can turn off a few of them.
Here is a link to a site that has a list of the default set of services and if you can turn them off or if you should leave them.5. Oddly this should have been the first thing that I listed, but what the hey. Now that space next to your clock is called the system tray. How may things do you have running there? How many IM's (insteant messengers) do you have loading and runing on start up? If you have more than 7, you may need to have a look at your start up folder, and a few other places, and turn off a few of those programs. Especally if you don't use them everyday and it's not needed for the health of your computer.
That is basic trouble shooting. Hope one of them help you out.