Sitting on my computer last night and screen turned black. I had been poking around mcafee looking at firewall config but hadn't changed anything. Could BARELY make out display, but 90% sure the only thing displayed was my desktop. Could see task manager pop up when I hit ctrl alt del. Restarted computer and was fine. Happened again to my husband today. restarted computer screen was fine til it reached desktop after startup and then turned dark immediately.