Mustang GT 2005 won't start =( on 2005 Ford Mustang GT

I drove my GT yesterday as work, then to the Mall, I was on a car jam, then the supermarket. After that, when I tried to start it..NOTHING...just a "click"sound and everything else turns on (radio, lights, alarm), but the car just won't start! It has happened to me before, but this time nothing seems to start the car.HELP!!!

Asked by for the 2005 Ford Mustang GT
Start with the battery. If a jump doesn't help, then you will work your way back up the starting/charging system to the starter, etc.

If it is not the battery, you should take it in to be worked on.
2 answers
Sounds like a bad battery or a dirty/loose battery cable connection. You may also have a problem with the security system, but I would look into the battery first.
Have you tried jump starting it?