I regularly have a problem when switching between users in Vista - the screen resolution drops down to 800x600. If I try to set the resolution back to the maximum, it says nothing, but just keeps it at 800x600. I can set it back to an intermediate value. Otherwise I have to either restart the PC, or sometimes if I log off one of the users, I can then set the resolution back to max.

Might it also have something to do with using sleep mode instead of performing regular shutdowns? I thought it might be related to the desktop background image taking up too much space, but even with plain colours, the problem still occurs.

There is an enormous thread on this here, but not really any answers.

From what I can gather from that thread, it isn't related to any particular applications, nor limited to a particular make of graphics card or monitor, so I don't think that including hardware details is useful.

This is a very annoying problem, as it screws up my desktop and screen layout every single time.

Has anyone here experienced this problem or found a solution?

I've noticed that Windows Update has tried to install nVidia updates and apparently they've failed on several occasions. Not sure if that is of any relevance or not.

UPDATE

The last post on the thread:

FWIW - I had this problem for about 2 years and wrote a number of posts in this thread in the past. It survived OS reinstallation, change of practically all of my hardware piece by piece (mobo, cpu, monitor, graphics card, memory, power supply...) I used to be affected by this annoying problem at least once every 24-48 hours.

About 1.5 months ago I wiped out my 32 bit vista ultimate installation and installed Windows7 ultimate 64 bit from scratch and never saw this problem again. GOOD RIDDANCE. Vista was a pathetic piece of __ that felt like a flashback to the old [horrible] NT4/Windows95 days. I was seriously considering switching over to Apple/Mac OSX if this problem persisted.