alternator, battery, or other problem?

2000 Rodeo, LS, 4x4, 120,000 miles

Symptoms:
Running fine with no issues yesterday.

This morning, turn key to start - no power at all, no crank, no click, no dash lights, nothing.

Jumped from the wife's car, starts fine, lights and radio, etc. work, but same problem when I disconect from the other car and try to start it again.

After it sits - a diode in the electrical compartment under the hood (where the fuses are)is vibrating and humming.

Thoughts?

Thanks in advance.


Follow Ups:

Your battery has low power, which is probably causing your "diode" or whatever else it may be to hum. If you left something on then it's probably just really drained and needs to charge for a while.
Doesn't sound like an alternator simply b/c it was fine yesterday and is now simply dead. I've had cells go bad in my battery before literally overnight, to the point where the car was undriveable the next day. Just take it to advance or autozone and let them test it for you.

if you are still rolling on the OEM battery you are over due for a replacement.

if you are still rolling on the OEM battery you are over due for a replacement.

sorry, I should have mentioned that the OEM battery was replaced 2 years ago with a battery from autozone. I will be taking the rodeo over there tonight - hopefully it's just a dead battery.