Will need some more info so a couple of questions:
Vehicle (model & year)?
Have you tried to reattach the stereo to see if that restores anything?
When you say no power, are you referring to no power at all (e.g. dome lights) or just no crank/no start?
Do you know if the non-Bose stereo (brand/model?) is a plug & play replacement for the OE radio or if there were wiring/harness mods required?