car stereo doesn't power on neither does my amp?

[blinkinsam]

i changed my head unit yesterday and it was working fine until i went to put it back in the dash-bored and its sparked,and then i lost my interior light,clock and bootlight,i changed a fuse and that got them working again but myhead unittdoesn'tt work again,i tried a oldhead unitt just in case i thought i blown it but that onedon'tt work eitherr now,and i got no power to my amps what it be??