No power to electrical

I was cruising in my 2002 mustang gt when I blew a spark plug. Pulled over let it run and found that out. Started the car back up and I left the coil plugged in but it drove home just fine except for the spark plug lol but I got home shut it off, all was still in working condition. Checked the codes. It said misfire cyl 2, emissions readiness test, cam positioning sensor and 2 others that weren’t really significant. Let the car sit for about two weeks and went to go start it and nothing has power. Couldn’t even get the dash to power on when pushing the key foward. Theft light was flashing though but it was dim. Can’t lock or unlock the doors unless I manually do it can’t move the Mirrors. No bad fuses and my alt is fairly new and just recently had it checked before my blown spark plug. Any suggestions?

It doesn’t have a anything pulling power away, the batter is fully charged ! I tried jumping it too and still nothing comes on. I was told to check the alternator for a bad diode by seeing if it’s overcharging the system? Battery terminals and everything I could see seemed to be in check. I just had it in the shop for a battery light issue but I had a bad pcm and my return line from the alternator wasn’t connected to the positive terminal which now it is. So maybe a ground came loose? Because my terminals and wiring harness are good and my battery is charged and even if it weren’t we’ve tried charging it and still the same issue.