Why would all the power windows quit working?

they should be under the dash but sometimes it can be a different name or more then one thing is run by same fuse escpecially on a newer vehicle

1994 camero dont have bcm on them 1996 and up does....

check your fuses. Or it could be a main relay located in the engine bay.

Do all these things quit working at the same time? If so, I would be looking at my main power circuits - like possibly a bad ignition switch.

check main power panel under the hood for aux fuse, should be in the 40 to 60 amp range possibly slightly larger than standard fuses.

Hi check your radio fuses

If all power devices stopped at the same time you may have a bad fuse link. Since it is rare for all the fuses blowing at once and you already checked them. Start at your fuse links before assuming something expensive.

Sounds like you could have an issue with a connector going into your BCM or possibly your BCM itself. There is a fusible link that comes off the BCM and it goes to your radio and power windows. Off hand i believe its circuit 75 if you have a wiring diagram and possibly a dark blue wire. On the passenger side kicker panel there is your BCM you can try to wiggle the connector and see if that is it or inside the BCM the solder joints could be going and in that case your screwed.

check for a good ground connection

I had the same issue with my wife's 01 beetle and it ended up being a bad alternator.