I just bought a used n900 that seems to have the usb problem:
-charging is fine with the 220v adapter
-no way to connect it through usb on a computer, "not enough power", it's not mounting on the computer. Tried Ubuntu, Mac, XP, laptop and desktop.
-sometimes freezes the xp, comes back to normal when unplugged.
-no way to fash the phone

I bought a new usb cable to check, it's my last hope. Anyway, I use ssh for file transfer, but is there hope I can flash the phone without usb to restore it to factory ?