Turn off your screensaver, you'll probably find that this is set to run every 10 mins - to turn it off, right click on your desktop, then left click on properties, then click on the 'screen saver' tab.
if this still doesn't cure it, boot into safe mode, and run it then it - to boot to safe mode, turn your pc off, then turn it on, as soon as you turn it on, keep tapping the F8 key, then you'll see a menu, use your cursor keys to highlight Safe Mode, then press the enter key
bcfctrev, April 2005