No, I used the cable and port assignment that works for my Uno R3 and my computer doesn't recognize the Mega 2560, Period... When I first plugged it in my computer wanted to install a CP2102 USB Driver and when I tried to "re-install" the heretofore "Working" Driver from the Arduino IDE install package the message from the PC (X86 Win7) was that it was not the right driver... Plug the Uno in and it works just fine. So it is my belief that the USB chip (the 8U2) is either defective or there is a problem with it's programming. I just tried again just now to U/L a sketch to the Mega 2560 and the same message was presented," No Device Found on COM 15" (My USB serial port) and I then reset the board ID in the IDE to Uno and plugged in my R3 and uploaded a sketch successfully. Same Cable, same work area, I only moved the boards about 4 inches, not the cable. The Mega had the Blink sketch loaded out of the Box and failed to be recognized immediately when I plugged it in W/ - W/O the IDE running. Most difficult as my 'Old Beady Eyes' make even looking at that chip difficult and my shaky hands make measurement a difficult task as well, well just a little difficult... IMO
Doc