Losing electricity

There's something weird going on. When I insert the key in the ignition, the little buzzer will sound for a second very faintly, and sometimes the warning lights on the dash will come on. Other than that, I have no electrical power - no lights or anything. When I go to start it, I lose all electrical completely.

I checked the fuse board, and there's barely enough power coming across it to warm up the tester. The battery is at full charge.

'86 2.5L 5 speed.

Help!

make sure the battery is grounded. if you lost the ground or there is alot of corrosion where the ground mounts you will not hafve any power.

That's the first thing I did. Still nada.