Windows 7: Random crash/freeze with dual monitors

Whenever I move my mouse along the bottom of my primary screen to my secondary screen, there is a chance of the mouse cursor glitching out and looking weird. When that happens, I would say there is a 50/50 chance of the cursor then turning into a square and soon after that my monitors turn solid colors and my computer freezes.

I have already tried moving the taskbar away from the area, and the problem still persists. I am using a Radeon HD 4670 graphics card, but I tested it with XP and it works fine. I tried the 9.9 and 9.8 drivers for the card, but the glitch still happens.

That sounds very hardware/driver-ish. Can you confirm whether it also happens if you go into "basevideo" mode?

BCDEDIT /SET VGA ON

You'll need to reboot at least once after running that command. (To go back to normal after you're done testing, use the same command with OFF on the end.)

Do I just put that in the Start menu box? I tried that and nothing seems different after rebooting. I was still able to crash the computer as well.

Open an elevated CMD prompt (right-click, run as admin), and run the command that way.

Okay, it worked this time, but I can't use my second monitor. Is there a way to turn it on in this mode? If there isn't, I can't test anything.

If it worked in "basevideo", that strongly suggests a problem in your normal video driver. That's what we just tested - a different (low performance/high reliability) video driver that's built into the OS.

You shouldn't try to add more functionality to basevideo mode (it won't work anyway). Instead, I'd suggest focusing on finding a driver revision that works with your setup.

No, I mean I booted into basevideo mode. That worked. I can't see if the problem is the driver or not since the crash happens when I move the mouse between monitors. I can't test it right now because I only have one monitor on.

Oh, right, gotcha. Still, it does prove that there aren't any no-go areas on your (primary) monitor with a different driver, so once again the card-specific driver becomes the main suspect.

Are you running any desktop "enhancers" perhaps? Ultramon, some type of 3rd-party desktop "extender", or anything like that?

Actually, I was running Ultramon for a period of time. I turned it off to test whether it was causing the crash, but it did not happen for the few hours I had it off. This was before I found out what caused the crashes, though. I then switched to Displayfusion, but I never tested that.

I did try moving the taskbars to the top of the screen, but the mouse moving between screens at the bottom of the desktop still caused the crash. I'll switch back to the regular drivers and try causing the crash without Displayfusion on.

But now I can't get my computer back to normal. I tried BCDEDIT /SET VGA OFF, but it doesn't seem to do anything. I still can't turn my second monitor back on.

Edit: Okay, so I did BCDEDIT /SET VGA ON OFF, and the resolution went back to the smallest setting. I still can't get everything back to normal though (Second monitor).