Vista "reset" user account after boot

I just booted up my Vista x64 PC ten minutes ago and got a bit of a scare. One of the applications I have set to launch automatically on startup popped up its initialization window as if it was the first time it was being used with this Vista user account.
A few other applications hadn't launched at all (probably indicating that they would need to be set to do so manually for each user), just like my mouse settings were different (back to default) and my user icon in the start menu had changed.

I didn't investigate further, but promptly logged out (where the login screen again showed the correct icon for the default account - and there's only one, aside from "guest") and logged back in, where I could fortunately take a sigh of relief, as everything was back to normal again.

Has anyone ever had this happen? I've never seen it myself in the year and a half I was using Vista 32-bit on my laptop.

Hello Miths,

Did you see something like this error message when that happened?

http://www.vistax64.com/tutorials/135858-user-profile-error-logged-temporary-profile.html

Your user profile was not loaded correctly! You have been logged on with a temporary profile.

Changes you make to this profile will be lost when you log off. Please see the event log for details or contact your administrator.

Click to expand...

No error messages of any kind. The few things I mentioned that made the issue apparant to me, pretty much just made it look a bit like I had just logged in with a new account.
Although thinking back I'm 99% sure the desktop wallpaper hadn't been changed to a default image - so I guess it wasn't quite like I was starting with a blank slate.

And obviously - since the account worked fine again after logging out and back in (and I also tried a full system reboot after I made the post above, no account problems) - all the user files and folders were still intact.
But perhaps Vista somehow failed to read most of them when the issue occured?

I hope it doesn't happen again - or at least that it will be just as easy to fix - but I'm obviously still curious as to what might have caused the issue?

Not sure. It may have been a service that just temporarily failed to start. If it happens again, just post back with any details that you notice about it.