fucking microsoft shit.
i bought some machines to sell on ebay, with linux pre-loaded. it turns out that, if you do that, that windows cannot be installed on the machine.
apparently, according to this, HP have had a practice of 'tattooing' machines.
The symptom is that any OS _other_ than windows on the machine causes the XP install to go 'blank' and shut down the machine after it checks the hard drive.