I would like you to download Process Explorer from the SysInternals website. This program will allow you to see, in real-time, what programs are accessing your processor and should give us a hint (if not the answer) to what is causing your CPU spike.
1. Navigate to the Process Explorer website.
2. Scroll to the bottom of the page and click on Download Process Explorer (1.5 MB).
3. Save the .zip file to your Desktop
4. Double-click the .zip file to open it
5. Select procexp.exe and Extract it to your Desktop.
6. Double-click procexp.exe from your desktop.
What you will see is a listing of every process currently running on your machine. I'd like for you to watch the CPU column and note which process grabs your CPU time every ten seconds. Watch for a couple minutes or so and make sure that nothing else (media players, etc.) is running on your PC. Post back and let me know which process(es) is/are taxing your processor.