D820 Video falls back to 640X480 resoultion can't change it its happening to 15+ Windows XP machines

Just this week we started getting getting calls that the resoultion on peoples screens is set to the lowest it can be and they can't change it to a higher setting. They are all XP machines.

Everyone has local admin rights.

On some of the systems a reboot worked to get things going again.

On some systems we had to remove the display driver (nvidia) and reboot. The machine would come up like normal again, until the next reboot or the third reboot or fourth...

We've tried removing the display driver and getting the latest one from Dell. Same issues. Might work once after a reboot or a few times then it'll fail to 640X480 again.

I've rebuilt a machine from the ground up with all the latest Dell drivers for everything and after a bunch of reboots it's still going to the low res.

Some machines were built in 2006 with few updates, the last full rebuild I did was Wednesday. It worked for 5 reboots but she called this AM with the same issue. I uninstalled the driver and rebooted and she was OK again for now, likely until the next reboot.

If this was one machine that's be fine but it's not its 15+ now so far this week.

If it was because of an update that's fine because we'd be able to roll it back but we make sure nothing is updated automatically. Given that some PC's haven't been touched since 2006 and others that were fully up to date are both failing it's got us stumped.

Has anyone heard or seen of anything like this before? We are at a loss as to whats causing the issue with all of them this week. We also have some very frustrated users that can't work when they get in in the morning.

Any thoughts?

Thanks for any help.