|You should definitely scan for spyware to make sure your computer is not infested. This can cause multiple programs and process to be loaded into CPU access and RAM thus making your CPU usage high. However, you should monitor it to make sure that the spikes in usage are temporary or constant. Constant would indicate a virus. Monitor it by pressing Ctrl-Alt-Del. This brings up the task manager. Check out the link below to see visuals.|
Here are some ways to cut down down on CPU access
Disable the amount of services running in the background-- You can do this by altering your computer configuration. Here is how:
1. Open your Start menu.
2. Click Run
3. In the command screen type "msconfig.exe"
4. In the "system configuration utility",click either "service" or "startup" tab
5. Uncheck all programs that your are no longer using.
6. Click "OK"
Hope this helps!