01Silho Suddenly No Function on Door Locks, Power Windows, Interior Lights, Alarm Sys

[koonceman]

runaround HELP!!! 2001 Oldsmobile Silhoette, 140,000 mls. Suddenly the pwr door locks (wont work from the door switches or the clicker), windows (front and vent) wont function from the door switches or the overhead rear vent switch, interior lights wont turn on at all, alarm system (wont engage) and the radio goes off as soon as the key is turned off when it has always stayed on until the doors open.
I thought fuse at first, but those are fine. Stopped by Autozone because the check engine light was on... nothing to do with this it was the ERG Valve. They suggested that it might be a relay or door lock module. So, I stopped by the dealership to get an opinion.... the service dept. manager said possibly door lock module or a pass key sensor issue. However, they want $150 to diagnose the problem and somewhere around $400 to fix the problem.
Anyone else have this problem? I could use some help. I just don't want to drop $550 in coin for a possible $5 fix.