can someone help me figure out what is wrong?
 

I was driving the ABS light and Battery light came on then the radio shut off. I rolled up passenger side window but driver side would not roll up. Got home and the window rolled up. Next day battery was dead. What are the next step to diagnose the issue? Thanks!

sounds like u need a new battery.

sounds like your alternator and battery

What was happening w/ the volt meter? Alternator, battery and voltage regulator are the most likely culprits.

thanks for your help, here is the latest...
 

My Battery is fairly new maybe five months old. I have a battery charger and charged the battery up. The car started but the voltage began to plummit after a couple minutes I am pretty sure it is an alternator issue. How hard is this to replace? I am pretty handy and dont want to go to the dealership and pay the quoted $1000 for a new one. Thanks again for all of your help. 2001 c2 seal grey/black.

Alternator is not too hard to do if you are a little handy. Look online (google search by the part number) for sources other than a dealer. The OEM price is over $1,500. What year is your car, I can look up the part number.