Late yesterday afternoon, a few of our users were experiencing weird graphic issues in Revit - things like inverted colors and JPEGs not displaying correctly. We're all running Dell Precision M4600 mobile workstations with AMD (ATI) FirePro M5950 video cards. Turning off Hardware Acceleration helped, but Revit was still somewhat glitchy. This morning, all but a couple of our Revit users were having the same issues so I had them all turn off Hardware Acceleration until we figured out a solution. Updating the video drivers didn't seem to help, and I'm all out of ideas. Seems strange that everybody started having issues at once, but that's why I was thinking an outdated video driver.

Any suggestions or things I may be overlooking?