Mitsubishi Repair: Electrical problem, greddy bov, last nerve

Question
Here is a tough on for you. I've been working on my car for about a year now and everything has been going good on it electrically and mechanically then one day I was driving around and my aftermarket  cd player shut off and turned back on.. it kept doing that for a bit until i powered it off. I shut my car off and then turned it back on and it turned back on but did the same thing. So i kept it off for the time being because i didn't want other things to start going wrong. About this time my dome light decided that they wont turn on.. and when i open my door, either side, there was no dinging sound that you would usually get. also, when i locked my doors, the security light comes on but now it doesn't and i always had an engine light that is on but now that doesn't come on anymore, only when i turn the key but right when i start it, it turns off. there are a few times if i turn the key over, not all the way over and wait a bit, then start it, the engine light would stay on. the engine light is for my rear 02 sensor so i know that is not the thing that causing this. finally, i was with a friend and we stopped somewhere to eat and before we went in i decided to turn my cd player on. it worked but then my friend opened the passenger door my aftermarket cd player shut off, i told him to shut it and when he did the cd player turned on. Now, the cd player doesn't turn on at all and i have done a bunch of stuff already to trouble shoot.  This is what ive done so far is i checked my ECU to see if there was any melt capacitors but it was all fine. took off my door panel and everything seem to be fine. Looked underneath my dash and all the wiring that was visible looked like they haven't been touch since its been rolled out of the factory and its very clean. Checked all my fuses and they were good. used a 12v voltage tester on all of them too and that was good. The only aftermarket part on the car is a Greddy bov and aftermarket cd player. I have been on my last nerve trying to figure this out,I even been on Mitsubishi forums and posted the same thing I am saying to you but I got no where.

Answer
Justin,
You should first have your charging system tested.  A bad battery or failing alternator can cause this.  Major auto parts stores like AutoZone can perform these tests for free.

Also, an improper ground or loose battery cables can also contribute to this problem.  Check the ground wire on your CD player.  Sometimes those aftermarket cable harness adapters have poor grounds and you should use a secondary ground attached directly to the car's chassis.
Good luck!