Is my Arduino broken? [serial port already in use problem]

Using Arduino Interfacing w/ Software on the Computer
4

Another 2 things i can say:

  1. It's not the wire - i've checked other one, still nothing.
  2. I've cleaned the com port in regedit (http://blog.cognitioninfotech.com/2009/01/how-to-clear-or-reset-com-port.html), after that I removed Arduino from COM3 in COM & LPT Ports in Device Manager, reboot computer, instal it back with the driver, reboot computer again and...? Still:

'COM3' already in use. :frowning:

I'm starting to think, that the next step would be the system format :confused: