bombalooza

thanks for your suggestion.

may be you are right that it could be a fan issue. because the problem starts only a couple of hours after the computer has been running.

and yes what i did was a system restore to a point where i thought the updates hadnt been applied yet.

i am going to try the livecd approach with linux. but reinstalling vista is way too drastic as i have a manufacturer's installation and dont even have an install cd. plus all the data and settings will be lost which will mean a lot of hard work getting everything up again.