Car won't start

Thank you Roy.

SNC

My 2000 Mitsubishi Galant is a great running car and I didn't have any problems with it until this winter, every time I went a day without running it it would not start unless I jumped it with jumper cables, then one day I was trying to jump it with a 85 crown victoria and sparks flew when I tried to put the cables on and the horn went crazy like someone was laying on it. I then replaced my battery with a new one and tried to jump it the next day but after being started it turned off after ten minutes then the next time I tried to jump it it started but as soon as the cables were taken off it would shut off automatically and would not stay running. Some say it's the altinator and some say it could be the starter can you help me?

2000 Mitsubishi Galant 4 cyl Front Wheel Drive Automatic 130000 miles

This same problem happened to me in April of this yr (2010). I went out to start my car, and it would not start. Just one little click, and then nothing. It appeared the battery was completely dead--I couldn't even use the power locks to lock/unlock the door, it was so dead.
I changed out the battery, and lo and behold, that one lasted only a day and a half before it too was dead. So, I changed out the alternator (May 2010), and got a brand new battery (since the crappy old alternator had caused the other replacement one to be completely drained). The car has been running/starting fine.
Now today (Nov 2010), I go out to start my car and take my child to his bus stop, and "click". Then a whole lot of nothing. Just for the record, it was a brand new alternator I put in the car--not from a junkyard, not rebuilt. NEW. And the battery was also new.
I know the temp dropped overnight to about the 40's (last nite). But that was not the case when my car did these same shenanigans last April. I live in Florida--the temp then overnight was probably still in the high 60's/low 70's.
What can be causing this? Surely an alternator should last more than 6 months? And a battery? Should I replace my gasoline with Holy Water, or what? Help!

2000 Mitsubishi Galant 4 cyl Front Wheel Drive Automatic 120000 miles

HEY GUYS, MY PROBLEM IS THAT EVERYTIME I START MY CAR IT DOES ITS NORMAL STARTING AND THEN ABOUT 5 SECONDS AFTER THE CAR TURNS OVER IT DIES. ALL THE LIGHTS ON THE DASH STAY ON BUT THE CAR DIES. I TRIED TO START IT AND GIVE IT A LITTLE GAS BUT IT DOES THE SAME THING. IT TURNS OVER FINE BUT THEN THE MOTOR CUTS OFF ABOUT 5 SECONDS LATER. I'M NOT SURE WHAT IT COULD BE. MAYBE THE IGNITION SWITCH OR MAYBE JUST THE BATTERY.

I'm not a certified tech. Or anything but it could be your alternator.