I have this old car with a fairly old and dead battery. I have a little box that plugs into wall outlets to charge batteries, but the directions specifically say not to use on dead batteries or some unnamed horror may befall you. :confused:

So what constitutes a dead battery, and how do I know if mine qualifies? The last time the car was started was about 4 years ago. It was cranked later, but it hasn't been run since. Won't turn over now, or power any electronics. Do i risk trying to jump it?

If it's a conventional battery with liquid electrolyte, don't bother trying to resurrect it. If it has been sitting that long in a discharged condition it isn't going to be any good. Dispose of it in an enviromnentally sound manner and get a new one.