notebook will only start when running on the battery and not when plugged in

[faceman]

Hello
My Notebook will not turn on when the power is plugged in. It will only power on if the power cord is unplugged
So I just turn it on without the plug and once it starts up I just plug the power back in and the PC has no problems
What is causing this?
The Computer is a Lenovo X300 Win Vista
Thanks in advance

 

[MindoverMaster]

Might want to try getting a new A/C plug. Otherwise, it might be your PSU. Connection between your plug and battery.

Is the laptop under warranty, at all? If it's Vista, probably not, I'm thinking.

 

[faceman]

Thanks for the reply
No, it's not under warrenty