OK, sounds like something quite unique or perhaps a corrupted install.
If everything is standard on the machine - no odd peripherals of any nature, plain xp install without any odd third party programs or security systems or windows enhancements (blinds?) and no other apps running (net meeting or remote desktop in particular) I would try a fresh download and install.
If everything is standard on the machine - no odd peripherals of any nature, plain xp install without any odd third party programs or security systems or windows enhancements (blinds?) and no other apps running (net meeting or remote desktop in particular) I would try a fresh download and install.