[DA IMP]

Hello,

This issue has been around for a couple months now, but I'm unable to find a real pattern behind it as of today. Seems to happen at random. And on multiple computers with different hardware builds. Most frustrating, it never seems to happen when I'm available...and I'm the office's tech assistant, so I'm around a good deal of the working day for this very purpose.

This computer wasn't either built in hardware or software by me. I found the whole system to be decent enough in whole, to not bother with re-installing everything myself. It came with SP2, and I think it lacked a lot of patches originally but I already took care of that. On other computers with this same issue, the patches had to be installed manually (the firewall and proxy we run through makes the Automatic Update tool work only occasionally), and the problem came only after that...

Just to clarify, we're talking with typical blue screen king of login where you don't have to type your user, and quick switching without logging off is allowed.
When a user comes out of their session through either loging off or simply doing a quick switch, or when the screensaver does the quick switch for them...sometimes this causes the logging in back to be impossible, as you just cannot type into the password field. The keyboard does work, the lights turn on and all, but it won't let you type a thing. In any user. It *seems* to happen more often when the quick switch was caused by the screensaver, but as I said before, no pattern is apparent yet.

Needless to say, this is troublesome, as the only way to escape that is rebooting, thus losing any unsaved work. So far I can only prevent it by disabling all settings that would make the computer switch out of the user on its own...fortunately, this computer has only one active user, so with that I gain myself some time to work on the issue...but it really is better that the computer would switch out automatically after a while, for security reasons. Besides, I cannot rule out the chance that the computer will bring the issue even when the switching is manual.

I hope someone can point me out to whatever is doing this. I kinda suspect patches or other little pieces of software XP adds through the Automatic Updates, but a comprehensive search through Microsoft's Knowledge Base hasn't thrown any useful results. On any such issues that would relate to Microsoft, I've always gotten more efficient input here, thus far.

Thanks to all in advance, for your time and help.