I have 2 computer both running Vista. One has the 8600GT card. Last night I was getting no display, monitor said no signal. I plugged it into the Mobo VGA and had display. While I had display I updated the driver for the card. In hardware devices it said the display card was functioning, I updated the driver anyway and got the message it was successful and needed to reboot. I shut it down as it was late and booted this morning. I still had no display from the card and now I have no display when connected to the Mobo.
I tried on a different monitor, no change.
I reseated the graphics card, no change.
I reset the bios by removing the CMOS battery for 5 minutes, no change.
The second machine has the 9400GT card so I tried the 8600GT card in it just to be sure the card was bad and got the same result on this machine. When I put the 9400GT card back in. I got the same issue. No signal display on the monitor. I also get no display when I connect to the VGA port on the Mobo.
I reseated the card several times and reset the bios.
On both systems all the lights come on and flicker as normal, when i connect speakers during boot I can hear the windows chime so the OS is loading. Currently I am booting both machines with the DVDROM disconnected which leaves only the hard drive.
I already know the computers are running, I can hear the Windows welcome chime when they boot. I used different monitors which had their own cables so it isnt a cable.
The next day my son turned on the computer with the 9400GT card and everything was fine. haven't seen an issue with it since. There is no change in the 8600GT card though. Had it tested at a computer store it worked fine so I am thinking it is the motherboard.