1. did you go through all the fuses to make sure you didnt ground out something while under the dash?
2. would be odd for it to happen at the same time, but a bad crank positon sensor will cause the motor to just crank over and over and never start.
3. can you hear the fuel pump prime? (key "on" listen for a buz from rear)
1996 with 254k miles, L32 4" FWI -> ported N* -> Ported Gen V w/3.0" Pulley, Stage 3 Phenolic I/C, ZZP FMHE, 1.84 RR, Headers and 3" pipe to mufflers, F-body brakes, and lowered on Eibachs. -RIP
AMG C400 White on black -daily