JackNg updates on 7 January 2010:
I have changed to a known good fan from another IBM T42 notebook. The "fan error" is solved as I can heard the fan rotating sound, but the IBM T42 notebook hang problem after using it for more than 1 minutes still occurred.
I have swapped the hardisk (same Hitachi model and 60 GB capacity) that came with existing old Windows XP Professional OS previously used by another person. The IBM T42 notebook still has the hang problem. I booted the IBM T42 notebook to Safe Mode, and it did not hang. I suspected that the hang problem might be caused by a software or OS fault. Hence, I restored the C partition from a clean Windows XP Professional OS backup. The hang problem is solved as the IBM T42 notebook works normally now.
JackNg updates on 14 November 2009:
The IBM T42 notebook boots normally on November 2009. After I have login to Windows XP Professional environment, the whole screen always hang: mouse not moving, keyboard has no response, etc. It took me half a day to realize that it was due to hardware fault: the CPU fan was not working and the CPU overheat problem might has caused the hang problem.
I have referenced to the "IBM Hardware Maintenance Manual - ThinkPad T40, T40p, T41, T41p, T42, T42p" on steps to take out the fan assembly, clean it and put it back. However, the hang problem still existed. Seem like it is time to buy another notebook.
When power on the IBM ThinkPad T42 notebook, "fan error" boot up error message was briefly shown and the IBM thinkPad T42 notebook automatically power off. I took out the notebook keyboard in order to see the CPU fan. During power on, the CPU fan was running normally. However, the "fan error" boot up error message still appeared and the notebook still automatically power off.
It took me a while to realize that the "fan error" was due to the uneven surface of the table. I place the notebook on top of a table where the pop up table "skin" has tilted the notebook slightly upward. If I placed the notebook on a flat and even table, the notebook boot up normally.
