Well, as I wait for my new Motherboard to returned form it's RMA with newegg, I have been setting up my old PC for use by my girl-friend and her sister, thing is, I have created two profiles of course, enabled Fast User switching and have customized both profile desktops completely with Object Desktop/Stardock programs. WindowsBlinds, Icon Packager, CursorXP, ObjectDock, LogonStudio, Bootskins.

When I switch between the two profiles (both, after both profiles have been logged into and loaded, as well as if only one has loaded and logging into the other one for the first time this session) The screen goes black, my monitor registers it like it is off and goes into sleep mode, and it hangs there for a good minute or so, exercising patience, it DOES come back up and load eventually, so my question here is, whats the problem? Before you go into the whole "Well, you have too many programs going on!" explanation, I should tell you that I have tested this in safe mode, as well as clean boot (diagnostic startup, nothing but essential drivers & services) and I get the very same strange bug. Much trolling around on the internet have given hints to this actually being an nVidia driver problem, but nothing I've found seems conclusive enough.

Here is the rig.

AMD Athlon 64 3200+
1gig RAM
Nvidia Geforce 6800
1x80 gig maxtor 7200rpm PATA HD
XP Pro SP2+
Onboard Sound (Gigabyte Mobo *shudder*)
Onboard Lan
2xOptical drives, one Samsung DVD burner, one HP dvd burner with lightscribe.

Aside from being slow due to the lack of ram and generally outdated system specs, the system is stable, no bugs/random crashes/etc. I am a stickler for having all the latest drivers, so thats not an issue either. I have Spybot, NO3D, Norton 360, plus numerous other freeware crosschecks, plus I defragment on a weekly basis as well as clean my general windows temp files (Not the pref etcher or anything like that) and All In All, when logged in and loaded the user profiles BOTH work flawlessly, no bugs, nothing is slower than it should be considering the specs. It's just one of those crazy bugs that will slowly drive me insane to the point where the penguins come to take me away to my own private igloo in the Bermuda triangle with Elvis, Richard the Lionheart and that girl who played Tootie on the facts of life.

So, any ideas? Is it possible the user switching black screen hanging bug is an nVidia driver bug? Am I overlooking some mundane detail that gonna make me look even more foolish than I have already proclaimed myself to be this past few weeks on these forums?

P.S. Yes I have Microsoft's UHPCLean.

Colleague, you're not the only one in the Universe to have encountered such a problem.
I, although having slightly different system configuration, cannot use "Fast Users Switching" and see the black screen every time, instead of starting a new user session.
Didn't you, by chance, find a solution during the year passed?

No, unfortunately I have not found a solution to this problem, some time after I gave the PC to the girls I upgraded the ram to 2gigs (motherboard max) and it at least decreases the time of the black screen duration, even after all the nVidia updates from then to now and a good maintenance regime, the problem persists.

Still have no real idea what could be the main cause, so I am sorry to say I don't have any real insight for you.

This at least is not my PC anymore thankfully. I hope you get the problem straightened out friends, and if you do be sure to post it somewhere for the people like us who can't ;-)

Probably, I've got some good news (for myself, at least). Yesterday night, at 2 a.m. local time already, I started to check all the software being installed and realized that I had two video drivers working at the same time: NVidia and "ASUS Enhanced Display Driver". Just wondering what was going to happen, I killed the latter and... got rid of the problem!
They simply have been trying to do the same job, and resulted in gygabytes not downloaded while my son occupied the PC