I have a really bad habit of leaving my computer on pretty much 24/7 - it has a power save mode that kicks in after two hours but other than that it's on all the time. So this morning I came through to the living room to find my password prompt screen up - my computer had restarted itself over night. Wasn't too upset about that because Windoz updates tend to do that so I figured that's what had happened.

Put in my password and started frowning. It was taking forever to log in. Eventually it got through to my desktop wallpaper and... nothing else. All the folders and shortcuts on my desktop were missing. Went to the Start bar and chose 'My Computer'. Processor whirred for a couple of minutes and then an error comes up "Wndows cannot find '/null'..." My jaw hits the desk. I was just talking to someone the other day about maybe looking out for an external harddrive to store my music and graphics on but it was just idle speculation (no cash - brakes and exhaust on the car are probably more important) Tried hitting Start+E and got the same error message, tried opening up the control panel in case somehow my profile settings had been corrupted, got the same error. Tried to restart and it wouldn't. Gave up, crossed everything I have and pulled the plug.

Tried again. Took ages to log in, still no My computer or documents or music or pictures or webs or videos or desktop.

Tried again. Took ages. Wallpaper didn't come up - just a blue screen (but not the blue screen of death) and then, wonderful sight, all the little folders started appearing on my desktop...

Yay!

Anyone have any idea what just happened and how I can stop it happening again? I'll be here all day, burning every single piece of data I have onto disk. Just in case. I ran a virus scan on Friday and there was nothing, I'm running a SpyBot scan right now and apart from nCase which always crops up there's nothing. My PC's only about two years old, maybe three, and it was pretty damn good when I bought it, shouldn't be falling apart already, should it?