Question Power

YEs only the light
There should be a front panel power lead that goes from the button to the motherboard front panel header.
On the header(check the motherboard manual) there should be a diagram telling which pair of pins controls thr PWR light.
Possibly that cable has become dislodged, or otherwise damaged.

If you still want an indication that the pc is powered on, you can buy a remote power button like this:
https://www.amazon.com/Computer-LIT...cphy=1015068&hvtargid=pla-1479562963606&psc=1