Strange video issues

I'm having a few issues, and just wanted to see if anyone else has had this happen, or may know what causes it.

First, this could be related, I'm not sure, a few days ago I ran GPUZ and CPUZ, clicking through the tabs and realized my video card was set at Pci-Express x4 1.1. I reseated the card several times, cleaned the pci-e slot, then used my secondary pci-e power connectors, and finally it's running as it should @ x16. I'm not sure how long it was like that, the performance decrease wasn't noticeable. (I'm actually curious if it was just reporting it wrong, because my benchmarks were extremely close; Counter Strike: Source| Video Stress test 216fps at x4, then when I fixed it, 224fps. All settings maxed. This all happened two days ago, and has been fine since fixing it, but..
Now, and this never happened before, and started right after that issue, sometimes when I boot up, if I right click the desktop, and select 'Refresh', the screen go's black for a moment, for about exactly 1 second, not long enough for the monitor to say (no video), but close. Once or twice it did do that though. Once yesterday while browsing this forum, it started, but this time it only did it if I tried to scroll up or down a thread. I minimized my browser, and tried to select refresh at the desktop, to see if it was the same bug, and it did it, I had to restart the machine.
Then just now, today, I booted up, signed into my user, and exactly then, as it said loading, just as the desktop should appear, it did it, and it lasted a little longer, this time the monitor said no video detected, for just a moment tho. I immediately restarted, and here I am, the bug is gone.

Note: It doesn't seem to matter if it's a cold boot or not. I'm going to reinstall my video card drivers now, but somehow I don't think it will change anything, but who knows.

Any idea's? Thanks, and sry for the length!

Edit: The reason I'm leaning away from a bad Gpu, or dying rather, is the fact that Windows Vista, & Windows 7, both have an effect exactly like this, sometimes when the UAC comes up, the screen go's black, in exactly the same way, then go's to the dimmed out screen with the prompt. This is common and it's just, too similar to what's happening, I can't help but think they may be related.

I'm installing the drivers now, so it would be great to get some ideas, between now and when this happens again.

I can only guess at this, of course, but that certainly sounds like it could be a failing video card. But it could also be due to a under-powered or failing power supply or even bad or faulty RAM.

The symptoms are very similar to TDR events, but since you are not getting any messages (Display Driver xxx stopped responding and was recovered") then we can assume it is not that, for now.

Try the new drivers. Make sure you are doing a clean driver install when dealing with video issues.

Also test to see if advanced graphics trigger the events by changing the desktop from an Aero theme to one of the basic themes. When I refresh my desktop it is nearly instantaneous - I can barely see the flash. Your video is dogging down to perform that simple task.

Also, look in your Event Viewer to see if there are any Critical Errors or Warnings that might point you in the right direction.

Hope that helps.

No problem. Glad it's up and running.

Unexpected shutdowns can cause all sorts of mayhem. That is very likely a cause. That's why so many people use a UPS in areas where the power grid is chancy.