I've used a new cable, itunes detected.
Must be some problem on pc or iphone: (
I gave up
can you try powering it completely off, while unplugged (using the home/power button method), then hold the home button, and keep holding it while you plug it into the computer, still holding it, wait for the recovery logo to appear and try restoring to a stock firmware (probably 4.2.1, as that won't require any PWNED DFU modes, or shouldn't anyway).
Just keep in mind it is literally impossible to permanently brick an iDevice, unless you are really an amazing hacker messing with much more than the sandboxed iOS system, like kernel or iBoot and such

, save for hardware problems on the iPhone. I don't think you have that problem though, because you were able to get it in/out of DFU/recovery mode, and use it with iReb as well