Is this a known bug in Windows XP?

Yesterday evening, the strangest thing happened. I noticed that the clock on my Windows task bar said 5:37 PM. It seemed later than that but I didn’t really think anything about it and forgot all about it. Some time later, I noticed that the clock still said 5:37 PM but had sort-of forgotten the previous time. It seemed way later than 5:30 and when I looked at a real clock, it was 9:30. I tried rebooting several times, but it wouldn’t reboot. No BSOD, just wouldn’t get past the Welcome to Windows screen. I thought, “Oh great! I gotta buy a new laptop, now!” This morning, it booted fine and has been running okay all day. I remember it ran Windows Update a few days ago. Does anyone know if this is a known bug, especially with whatever the latest MS update is?