2004 ford focus stereo wont turn on?

my friend installed a 300watt amp and 2 12 inch subs we got everything together and had it working- it was playing music and it sounded great. we turned the car off to place the radio back in and hide the wires. when we turned the car back on, now my radio wont even play! checked the fuse in the back of the radio it was blown. so i went to auto zone got a 15 instead of the 10 that was orignially in my stereo. still no lights. no clock. nothing. all the wires are connect to the amp and subs and also behind the stereo. i despretely need help! its horrible not to have a radio in your car! :(