The alternator went bad a couple of months ago. I replaced it and the car started and ran fine. During a road trip on Tuesday, the battery and brake dummy lights flashed intermittently and eventually my serpentine belt came apart, luckily at an exit. The tow truck owner led me to believe that the alternator failed, causing the belt to shred.
Today, I replaced the alternator and put a new belt on. I started it and it ran fine for a few minutes. I put the cover back on the motor, satisfied in a job well done.
Later in the evening, I started it, intending to run an errand... car started right up, idled smoothly for about 3 seconds, then died. Now the car won't start. Belt and alternator look fine. Starter sounds a little draggy when trying to start it (just since it died), but car gives no indication it even wants to start.