Allow me to flame the Hewlet Packard helpdesk a bit while helping others with the same problem. This issue should be in their FAQ, but… well… it isn’t.
The problem is that you get random reboots, hangups or BSOD’s (blue screen of death). It happens on my HP Pavilion Media PC (8170.nl), which comes with Microsoft Vista.
The cause, or at least part of the cause, became apparent after I completely reinstalled the computer, including a hardrive format. It worked fine, but after installing the windows auto update nvidia drivers, the problem came back.
Turns out, nvidia offers much newer drivers on their website then windows update does.
