My thinkpad T41 worked very well till recently it started freezing and the only way to overcome the freeze is to press the power button down. When I restart by pressing the power button it does not reboot sometimes. It stays there with a blank screen and does not recognize the hard disk. Sometimes it reboots normally and then I can work for sometime but then it freezes again. I can also see that the screen distorts terribly before the freeze occurs. I have run several tests using PC doctor and some tests were interrupted by the freeze. Even for tests that completed successfully without the freeze, there is no indication of any problem. Is there any solution to this problem? I am running windows XP SP2 on 512 MB ram.