Laptop will power up on battery, but not while plugged in

swhitfield

TS Rookie
A user brought me her laptop (an Acer Aspire 4520) for start up speed issues. While dealing with that I noticed that after shut down, I couldn't power the machine back up by pressing the power button. I have to unplug the power chord and then I can power the machine up. Also, if the machine is in sleep mode the power button doesn't wake it whether it's plugged in or not. You have to unplug it AND pull the battery to bring it back to a state where it will power up.

I've tried every configuration provided to me be Vista to configure the power button behavior in the CP but no luck...

Windows Vista Home Premium 32Bit
AMD Athlon 64x2 TK-53 1.7GHz
1GB RAM
GeForce Nvidia 7000m