oops i made a mistake. do this.
i had this problem on my computer
right click on my computer, go to properties, click on the advanced tab, click the start up and recovery button, click the edit button next to "To edit the startup options file manually, click edit. Next to the line that says "Microsoft Windows XP Professional", add "/pciclock" without quotes. save it, click ok and then reboot. i have not had the problem since.