The wife was caught out by the web ads "virus".
She was on ebay and asked me to look at something on the screen and a fake antivirus program was on screen saying it found a lot of virus infected files.
It stopped every program you tried running including Task Manager and when I rebooted the computer it had replaced the wallpaper and stopped all non-essential programs from running again.
Could only remove it in Safe Mode by looking at the prefetch folder in windows to see which .exe files had been ran. It wasnt even listed in any of the windows startup files in msconfig and such. She also had an antivirus installed which did not stop it nor pick up on it when running a scan in safe mode.
Very nasty one but luckily easily removed once you found the malicious program on the HD.