1996 Geo Metro 4cyl - Lights and electrical items (radio) died while driving the vehicle yet the vehicle continued to run normal for several miles. After turning off the vehicle it would not re-start. Used jumper cables from another vehicle to re-start the vehicle, the vehicle again ran fine but very weak lights & radio would not work. All gages OK.

I'm thinking that the alternator is not keeping the battery charged. Put the battery on a charger overnight at 4 to 8 amps. The engine should now start. Take the car to your favorite auto parts dealer who would likely test the alternator for free. If you do need a new alternator, install it, then start the engine and test the voltage on the battery--It should read 13.5 to 14.5 volts DC. If it still reads 12.6 volts, the heavy wire from the alternator to the starter solenoid terminal (that the battery positive cable is attached to) may have a blown fuse link (a specially insulated small diameter wire). Hopefully, the link is hanging out of the wiring loom that the large wire went into and can be easily replaced with a new link.

Check for fuses and any of the fuse box´s the one under the hood and the one under the dashboard