Not a stupid question in my opinion, but like M1.1 I wonder if you are referring to a power-on stall, or "stall with power"? The only other interpretation I can put on a "power stall" is a compressor stall in a turbine engine which is something quite different.
Anyway, assuming that we are talking about a piston aircraft stalling with power-on, the main differences are what happens to the aircraft as it stalls.
In a power-off stall, the designer will have (usually) arranged things so that the inner sections of the wing stall before the outer sections. This reduces the tendency for a wing to drop at the stall, and the ailerons may (but not guaranteed) still be effective even though the inner sections of the wing have stalled.
When a piston engined aircraft is stalled with a medium-to-high power setting, the propwash will prevent the inner sections of the wing stalling first by reducing the angle of attack of the airflow past the sections of the wing in the propwash. The first parts of the wing to stall are now likely to be the outer sections and because they are further from the fuselage any inbalance in lift as they stall will provide a higher rolling force, hence a wing-drop. Also the propwash at these higher power settings will be inducing more yaw as it strikes the fin. The usual result is a more dramatic stall and wing-drop, and if mishandled, a possible spin.
There are other effects too, but the above covers the basics.