I started having problems after I upgraded windows and my video card. Before this every thing was running smooth. Since upgrade it may run 10 minutes or half an hour then screen goes black while running under windows 8. I have a dual boot machine, so i tried running under xp, it ran all day yesterday. How do I figure out what driver or software upgrade that may be causing the problem. I tried to do a restore, but since unit wasnt set up for it previously, it doesnt work. I have a dual core processor 5200 with 4 gigs memory 2.5 ghz. The video card is an nvidia dual monitor geforce 610 external. The unit also works well using the pcs video port.