[DukeZeus]

This actually happened 1.5 months ago. I have already fixed it but I just want to know what happened.

I had a WinXP Pro SP2 on a Compaq Presario C733TU. My problem was that one morning I could no longer log-in to my OS. This happened every time I did a warm or cold boot. After the boot screen and when I got into the log-in screen, it would take at least 15 minutes before my username and password box would appear. After entering my password, the following error message in a dialog box appeared (as near as I can remember it): "The [My Username] domain does not exist". After clicking on the OK, it shows again the log-in screen. Re-entering my password only triggers the same error message.

Facts:
1. My username was the only username available for logging-in.
2. I was able to log-in to Safe Mode.
3. I did not install any new software or hardware for the past week before this incident.
4. The last thing I did the night before this happened was use MS Word to make a report.
5. My AV was Kaspersky IS 7.0.125 and was up-to-date. I also had Spybot SD, CCleaner, TuneUp Utilities 2008, and Advanced Windows Care V2 from IObit installed.
6. I tried system restore to a date 1 week, 2 weeks and even 1 month prior to this incident and that didn't fix it.
7. I tried fixing the OS with my installation CD and that didn't fix it.
8. I reformatted drive C: and did a fresh install of the OS and that took care of the problem.

So far since I reformatted, I did not encounter the same incident. I have the same applications and security programs installed. My hard drive was partitioned into three and I didn't reformat the other 2.

I just want to know:
1. If this also happened to somebody else out there.
2. What did happen? Was it something I did?
3. Was it a virus, worm or trojan?
4. Is the same thing likely to happen again?
5. What should I do to prevent the same thing happening again?

Thank you very much to anyone who can answer.

[NeedKarma]

It sounds like a corporate network computer that was attempting to log in without being connected to its network i.e. cannot reach its domain controller to authenticate the user.