*Disconnect the battery
*Take the belt off the alternator pulley
*10mm nut on the back holds the power cable on.
*2 plugs on the back come off
*2 bolts hold the alternator on
*a good yank, and out she comes.
If you car dies randomly, that may not be the alt. It could be though. When the alt dies, the car will run off the battery for a short time. Not well, but it will run. Once the battery dies, the fuel system quits. Then the car dies.
Charge up your batt, go to a good parts store, and have your alt load tested. It is free, and they can do it while it is on the car as long as you have a good battery.....
Simple test. Start the car. If you are seeing over 12.6 volts (anywhere from 14.4 to 13.8 is normal) when you hook your DVM to both terminals on the battery, then the alternator is charging.
You might want to inspect your connections, check your batteries water level and look for any massive buildup on the lead plates. If your battery is over 4 years old, you should replace it anyway, just in case.
Scott