580i wont turn on!

Question

Was on AT&T. Company with a "box" unlocked it. BUT, it could not send pix on either network or as Picture Messages.I tried (foolishly) entering a code from the Unclock To Talk Company on the net. Didnt help, BUT when I turned it off, it would not turn on again. completely shut off. Cannot turn it on. As if I did it on purpose to keep it being used by a stranger.HELP??