【Help】Unexpected Shutdown

[xx86pro]

My T42-8ZU was shutdown without any sign when I was chating with my girl. It seemed like that the power supply was cut off abruptly, but my battery pack (100% charged) was on the machine then and there was no error with the AC adapter.

I pulled out the AC supply and pluged in, then tried to start up the computer but there was no action (the power LED kept off). I had to remove the battery pack then installed back (also pulled out the AC supply and pluged in), after that, the power LED was on. Then the computer was started up again and it seemed nothing had happend before.

What's wrong with my T42? Is that some hardware failures?

Thanks a lot!!!