Hi all, I need your help and advice on my Thinkpad X61 problems. The laptop will power on when connect to the charger and work fine without any issues, as well as charging the battery. Once turn on, I can unplug and work via battery without any problem. The battery can hold 2.30-3hours charge and in good condition according to Thinkvantage toolbox. However, if I turn it off, I will not be able to turn it on with battery - need to connect charger in order to get it power on. Another issue is that most of the time when I shut down Windows and the laptop turn off - after 2-3 seconds it will turn itself on again (this happen when on battery only, not happen if the charger is left connected) as well as if I turn it off while plug in with the charger and pull the charger out of the laptop - it will power on itself too. I have to give a long press on power button to stop it from keeping switch on by itself. Again if I do this, it won't turn on unless I plug the charger to it. I have tried changing power option in bios setting but doesn't help. I search online and see some people have exactly the same problem as me but can not find the solution. I hope that it will not be motherboard related - By the way, I also reinstall Win7 many times to determine if it is software related glitch but seem not to be the case.

To summarize my problems
1) Thinkpad will not switch on without charger
2) Thinkpad will keep switch on itself when disconnect the charger or while on battery power only - require a long press on power button or reconnect the charger to stop this behavior

Thinkpad X61 7675-CTO C2D 2.2Ghz, 2GB, 160GB, WWAN

Greatly appreciate in advance for all your assistance.

Try disconnecting everything that you can and see if the same thing happens. Remove the hard drive and any external devices and see if the laptop will start from battery. If you have a different battery try with that one.

Thank you for your suggestion. I have tried all those and already bought a new after market battery. However, it still behave the same way. I believe there might be some hardware malfunction in this case. Right now, I have to put the laptop in hibernation mode to avoid constant restart when away from power outlet. It is inconvenient but seem like only solution that I can think of now.

There is circuitry on the motherboard to control the functions you describe. My guess is that you have a blown power transistor.