Well I was driving my old car today (it's my sister's now) and while I was stopped at a stop sign the car decided to stall and die on me, and will not start at all. It will crank and crank but not catch, sometimes it will almost catch but will immediately die afterward. The tach moves when I try and crank it so it's not the cps. I even tried jumping it but it still wouldn't start. Ideas? Where should I start in order to try and find the problem?

A little background info on the car, it's a 1996 Buick Park Avenue with the 3800 Series II in it with about 150K on the clock. There's a lot of stuff wrong with it, first of all it's an electrical nightmare (doors randomly locking, windows getting stuck down, horn randomly going off, lights randomly going on and off etc...), secondly the abs light is on and the airbag light will randomly turn on too. Oh and just recently I was told that the oil pressure light came on due to it being low on oil, I'm not sure how low it was since I wasn't there when my sister put more oil in but the light is off now.