Sorry for the 1,000th thread about a Mustang not starting up, but I wasn't able to find a situation that matched my own, so I thought I'd give it a shot and see if anyone has any insight on this situation. '04 GT (edit: this is an automatic) has been starting up just fine, with zero indication of any problems, and is being driven daily. This morning, I drove to the supermarket, no issues whatsoever. Parked in front of my house waiting for my wife, turned the car off for a few minutes. Tried to start back up: nothing. No crank, no lights on the instrument panel. Totally dead. We have one of these no-jumper-cable jump starters that connects to the cigarette lighters of each car, so I tried using that. This did cause the dash lights to come on, and when I tried starting up, it would not turn over but instead I got a rapid-fire click-click-click-click-click sound. Next, I tried jump starting the car conventionally, with jumper cables. This did even less -- the dash lights did come on, but turning the ignition produced only a soft "coughing" sound and then nothing. At that point the lights went dead and any subsequent attempts to start the car, with the jumper cables still hooked up and revving the gas on the functional car, produced no effect whatsoever. Meanwhile, I noticed that while the cars were hooked up, but with the Mustang not only shut off but with the keys out of the ignition, there was an erratic but ongoing clicking sound that seemed to be coming from the dashboard. I then thought perhaps the battery had given out, so I bought a brand new battery and hooked it up. Started up -- nothing, totally dead. No lights, no sounds. Tried hooking up the jumper cables again just on the off chance the new battery was drained. The only effect was, initially the same thing happened as previously, where the dash lights did come on when I turned the key to "on," but if I turned it, the same soft cough and then totally dead. This problem is baffling to me. It's a brand new battery, and everything had been working fine up to the moment it didn't. There were no signs of anything failing, and it had started up fine just minutes before everything died. I'm wondering, given the circumstances, what are the chances that it's a blown fuse? If so, which fuse or fuses could it be? I looked at the starter motor relay fuse in the power distribution box, but I can't tell from looking at it whether it's OK or not. I don't have a volt meter so I don't know how to tell if it's bad. Another problem is that I've got more time than money or automotive knowledge. Having this car towed to the mechanic to replace the starter or alternator will be very hard on my finances right now (since I already bought a new battery), so I'd like to try any cheaper possible fixes before taking it to the shop. I've looked at DIY guides to replacing the starter on this car, but it looks pretty daunting since I've apparently got to get underneath the car and get up into some tight spaces. Any help would be greatly appreciated.