MBP 13" Early 2011 Power button concern

[ZrRock]

I have an early 2011 13" macbook pro with an extremely odd issue. When it is plugged in, the power button doesn't function, but when it is unplugged, the button functions completely normally. Does anyone have any idea why this may be?

 

[hamiltonDSi]

Very odd, it seems like o software issue, you should wipe the HDD and do a clean install, perhaps Mountain Lion is a good choice if you don't already have it.

Edit : You can also try to repair the permissions, do some cache cleaning with Onyx, SMC reset...
Maybe, just maybe it would work