I have a 1997 Buick Century I was driving and.

TEST BATTERY AND CHARGING SYSTEM

YOU CAN DO THIS YOURSELF TO A "POINT" WITH A INEXPENSIVE DIGITAL VOLTMETER.

http://www.youtube.com/watch?v=a4NvKBiUc70

IF YOU CAN GET ANOTHER GOOD BATTERY/ OR FULLY CHARGE YOURS (IF IT'S GOOD) THEN INSTALL IT IN YOU CAR. DRIVE TO THE NEAREST POPULAR AUTO PARTS STORE FOR MORE INVOLVED TESTING OF THE BATTERY AND CHARGING SYSTEM...THEY WILL USUALLY TEST BOTH FOR FREE.

IF YOUR BATTERY SEEM TO BE FINE...IT COULD BE CONNECTIONS...LOOK THIS OVER

https://www.2carpros.com/questions/1994-jaguar-xj6-ignition-key-turned-car-doesnt-crank

RETURN WITH GOOD NEWS AND RESULTS OF YOUR TESTING...OR WE WILL CONTINUE

THE MEDIC

The oil light came on because the engine died an oil pressure was lost. As far as the electrical issue, does anything electrical work?