We have 2 PC in the family that are experiencing the same problem.
The PC's are only a few weeks old. Up until a couple of days ago, after booting up, the XP Welcome screen appeared with a warning box (Yellow triangle with black exclamation) but displayed no message. The cross on this box was greyed out and left an option of either clicking Yes or No. On selecting no, the PC carried on as normal.
Now on booting up, it gets to the XP welcome screen and an Error box comes up (Red circle with white cross). The options are the same but regardless of whether you click Yes or No, the PC does the same...
It flashes the wallpaper of the desktop, but displays no icons on this at all. It then reverts back to the logon screen and options are to try logging on again or log off.
Log on again results in a looping of the same error process.
Log off, closes down the machine.
Obviously this makes these PC's completely unusable at the moment. Can anybody help???????
Can't log on our machines 
