2003 Ford Focus Electrical Woes

My battery light had been going on and off for a while, and finally the electric went out. Took it to the shop, and they replaced the alternator and battery.

Only a few weeks after the alternator replacement, the instrument panel would shut off periodically for a few minutes and then come back on. A few weeks after that started happening, the electrical system went out altogether and the car won’t start.

Since I already sank some cash into the car for an alternator and battery, only to have the car quit running a month later, I wanted to see if anyone had any ideas before taking it back to the mechanic.

Any ideas what could be happening?