Probably.
The power button is connected to the motherboard via some 'armed' little cables, to a front panel. You can try to pull up and reseat them back again. I wouldn't exclude even some of them being in the wrong place, you can see what is the ordering for ur motherboard in the internet.
It may not be even necessary; if you make some disassembly, the power button himself most likely has a cover, and it may have to be reseated, tho this one is less likely as u say the button does work, just wrong.
In fact, was your PC working normally before? I mean, did this happen suddenly, out of the nothing, or the PC button has never worked normally before?