Please help, this is probably not the firts time this problem appears, the background on a XP Machine is just the picture, all icons, toolbars etc. dissapeared. Signon as administrator, if task manager gets activated then box indicating console appears. Not the windows keys on the keyboard reacts. Can the desktop be restored without having to do a total reinstall.

Thank you

I would try booting into safe mode. Since you can't really get anywhere to run antivirus, safe mode will only load the neccessary components for your machine. The you would be able to run anti virus/antimalware programs to see if you have a virus or malware.