ok, so the past week or so it's been getting colder. I am in Rochester for school and I had the car last year with no problems. Now I am having problems with my electrical system. Im not sure if it's the starter of alternator r somehtign else, but here a the symptoms:
When car would start, headlights would be dim, stereo would shut off while driving. Motor would not shift and would surge and make banging noises. Now the car will not start at all. I ried getting a jump from my friend's volvo and it wouldn't work. The lights in te car will work and i can turn on my radio, but the starter will either click, do nothing or turn the engine once and then keep clicking. When thinking about what could ahve caused this besides cold, i remembered that i left my lights on about a month ago and ran the battery down. When I went to jump it from my friend's GTI, he put the cables on backwards and the cables went hot red for a minute. The alternator is only 20k miles old (maybe 3 years), Im not sure about the battery. Please help

 

Sounds like a bad battery. Often times hooking up battery cables backwards will cause a short in a cell. I would pull it and have it tested. Replace if necessary. Then make sure you are getting around 14 volts at the battery when the engine is running. A bad battery can quickly kill an alternator, and visa versa.

 

Looks like it was the alternator. I had both that and the battery tested, the alternator rattled and squeaked, new one in now and everything works fine. Thanks for the help

 

You should replace the battery, sound like typical low battery voltage

 

With the new alternator everything seems to be back to normal. Should I still replace the battery?

 

Yeah, I would. You wouldn't want to make that Alt work harder if that battery is going low.