Windows 7 Taskbar corruption

[ddot]

Occasionally my Windows 7 taskbar gets corrupted with a cascading like effect (see attachment). Happens every 2-3 weeks and usually after resuming from standby, although once it happened after a reboot.

• Logging off or rebooting with fix the problem

• A screenshot (using print screen) does not show the corruption (the attached picture was from taking a picture of the screen with a camera)

• No 3rd party programs have been used to modify the taskbar

• Graphics drivers have been updated several times to the latest release, but still no change.

Specs:

Windows 7 Pro x64

ATI Sapphire HD 4670

Intel i5 750

Gigabyte GA-P55M-UD4

Corsair XMS3 PC3-12800 (4 x 2GB)

Any thoughts? Thanks for your help.

-Todd

[cluberti]

If a screenshot doesn't show it, that would indicate the problem isn't in the data in the DWM memory buffer, but exists in the memory in the video card or it's driver (or both). If it's not a hardware issue, it's definitely a driver one.

[ddot]

Thanks cluberti.

I should also note that I haven't seen any other sort of graphics corruption anywhere else. I'm leaning towards a driver issue, but part of the problem is I've also been unable to consistently reproduce the error, making it difficult to pinpoint it on something specific or a specific series of events. Even if a driver update was to fix it, I have no way of knowing either way unless it was to pop up again days or weeks down the road.

To maybe help rule out the hardware issue, does a memtest86 (or similar) for video cards exist?