Saturday night... well Sunday morning I got dropped back off at my car after a night of fun. First thing I notice when I got in is that the battery is completely dead. Finds out that I left my fog lights on all night. I get a jump and everything seems fine until I get about a mile down the road. Voltage instantly drops down to about 10 volts and slowly continues to drop until the car finally stalls and I coast into a parking lot.

Obviously the alternator stopped working/charging and the engine was running off the battery only until the battery was completely dead. Today I replace the alternator thinking that it would solve my problems and give the car a jump. Basically the same thing started to happen again and I turned off the car before the battery is completely died. I start it up again and remove the cable from the positive terminal and the car instantly dies. So it is a problem dealing with the alternator. I detached the battery positive cable from the back of the alternator and checked the voltage and it read basically 12 volts so that can be ruled out.

So what is the next thing I should start looking at/checking?

How are the connections? Any corrosion? Make sure to check BETWEEN the two red cables where the battery post is.

The new alternator may have gone bad. It sounds as if you didn't charge the battery before starting it with the new alternator. A dead battery can kill a new alternator. A battery that is almost dead can still read around 12 volts. It just can't put out the current that is needed. Checking all connections in the charging system is a good idea when replacing the alternator

Edit - check the voltage at the battery posts with the engine running. If the alternator is working, it should be between 14 and 15 volts.

All the connections were checked over and are fine. The alternator is def. not giving a charged. I'm going to try to replace the red top and alternator and see if that works.