Hello,
>
> I have a 94 sentra with about 120k miles. last night while shopping i
> tried to go home and the car would not start.
>
> here is a description.
> rubber burning smell.
> turn key, engine turns over shakes hard dies.
> engine dies when key is let go, but on a cold start it almost starts
> up shakes and turns off.
>
> smell is coming from the drivers side, new battery, new altenator and > starter. >
> lights work, radio works.
>
> does the a/c compressor have anything to do with this?
>
Maybe - was the A/C switched on when you tried to start the car? You mention a recent new alternator. I suggest you take a close look at the accessory belts and make sure they are all still on the pulleys. Either a seized accessory or a belt that has come off and is now wrapped around something would account for all the symptoms you describe. If you have a handy helper, get him/her to watch all the belt driven devices under the hood (from a safe distance) while you try to start it and see if the pulley is not turning on one of them.