Vista - Screens in Vista Business 64 Went Dim All the Sudden - Seems to Be Video Card.

I am having problems with the image on my screens. It seems more likely the video card as the image is alright upon boot but when I log in they get very dark and it is tough to see what is on them.

I'm running a GeForce 8600 on an Abit I35-Pro Mobo with a intel E6750 with 8GB RAM.

When this started happening I was watching Hulu (daily show) and when I maximized the video (screen) on the second monitor it went black and it said that monitor bios said that the cable may be unplugged.

I swapped the two cables on my tower to see if it was the monitor or the tower. The video switched to the other screen, so it seems to be the video card.

I tried to go into Vista graphics adapter settings and found that it would not recognize the second monitor unless I clicked on the advanced button which took me to the Nvidia advanced setup. I reconfigured the monitors so one screen would be an extension of the other and changed the resolution to the max.

When I would apply these changes and exit the Nvidia setup the monitors would revert back to only one working. I then tried the same thing 3 more times and then it started to come up dim when I would go to max res and 32bit (which is what it has been for 18 months). I switched the colors to 16 bit and the monitors went back to the normal brightness but when I closed the Nvidia screen it would go back to a single monitor.

I went thought the entire above procedure and got the screens to stay their normal brightness but had to leave the Nvidia controls open.

After about 2-3 hours, the monitors went dim. I rebooted and upon startup the monitor color was fine. As soon as the OS was loaded the screens went dim.

Anyone know what is going on?
I recently installed Sophos AV and some strange things started happeneing.

Would running hijackThis help?

6 Days...
Did you fix this?

No. It comes and goes sporadically. I want to figure out what is going on. It seems very odd. I have not been in front of the computer when it has recovered. I think that it once recovered by connecting to the machine via RDC.

If it continues I am going to install a new video card and see if it continues.

I have been doing tech support for 9 years and this is one of the more strange occurances.