Car Won't Start. HELP!!!

About a week ago I got a stereo system installed. 2 amps, a sub, new speakers all around, a double din head unit, and the metra kit for the ac and whatnot. About 2 days after installing it my car wouldn't turn on and I had to jump it to get it going. Drove home from work. Parked the car. Next morning got in and it turned on no problem. Got to work and the car was dead. Tried to jump start it but still didn't turn on. Bought a new battery and when I went to turn the car on the lights on the dashboard were flickering on and off in the key accessory position. Tried to turn the car on completely and nothing. Left it at my job(which is a body shop) and came the next day to see if it would turn on but now it's even worse. Nothing will turn on. Not the dash, not the emergency lights, nothing. Checked all my fuses and my fuses are fine. Before I call an electrician to come check it out I wanna know if any one on here has any suggestions. Please help!!

svergara, have you figured out the problem yet?