IBM T21 Sudden Powered Down Problem

[achilles21]

I have an IBM TP-T21 which sometimes hangs and sometimes
powering down. When it powered down, I think its not completely powered
down because the other LED near the battery LED lit. Until now I cannot find
which conflicts and causing the system to power down. Currently installed OS is Wndows 2000. Not sure if its powering down because of CPU overheat,
because sometimes even after few minutes of usage it will start to power down. I also encountered it under DOS sometimes, which makes me think
that its more of a hardware problem.

When I plug the notebook with the battery installed few hour before using
the notebook it will work perfectly, but after few hours of usage the notebook will start to power down and sometimes hang, even if i reboot
the notebook, it will continue to power down and sometimes hang.
Sometimes it will "on-off-on-off......." the system during POST.
Is this a symptoms of a failing mobo?

Anyone already encountered this problem?

[LtTPfan]

The mobo is certainly one possible cause, as is CPU overheating. Do you have temperature monitoring software installed? If not you can download MobileMeter for free here: http://www.softpedia.com/get/System/Sys ... eter.shtml