iPhone not detected by PC/MAC

Hello,

i tried to restore/update my iPhone 3gs with i Tunes. (from 5.1.1. to 6.0.1)

i do not know what went wrong, because i wasnt paying attention to the process all the time, however, the process ended in an error, sadly i dont remember the error code.

since then i have the following problem:

Windows 7 x64 nor iTunes will recognize my iPhone anymore. Also, its not shown in the Device Manager.

i tried:

every USB-Port, 2 different windows PC's and a MAC, on all systems the same Problem... iphone screen stays black and no signs on computer

tried to recharge on wall socket after 1 hour, no reaction from the phone

i updated windows, updated everything apple, uninstalled everything apple, reinstalled everything apple, restarted noumerous times in between, still the same problem

i connected various ipods and iphones from my friends, all are detected just fine.

* another problem i did not yet mention is that my sleep button is broke.. so trying the hard reset is not an option...

any idea, thanks in advance