arduino mega not recognized

Hi,
yesterday my arduino mega2560 (clone) stopped communicating t trought usb. Only ON and L leds are glowing, however arduino is ok because the last uploaded sketch is working. I thought that 16u2 was dead so I tried everything according to this tutorial http://arduino.cc/en/Hacking/Upgrading16U2Due. I was using my original arduino UNO as ISP programmer

I got this message from cmd:

So I think that when I was able to upload new firmware (I uploaded Arduino-COMBINED-dfu-usbserial-atmega16u2-Mega2560-Rev3.hex from arduino folder) the chip should be ok, am I right? But I am still not able to get the chip to DFU mode by shortening those 2 pins from 16u2 ISP connector.

I can,t see the device mega2560 in control panel at all.

My question is if the 16u2 is dead or not or where else could be the problem.

Thank you very much for your kind help.

I've got WinAVR onmy hard drive but I've never used it. What's wrong with the Arduino IDE? Or even GodHelp Us Atmels Studio 6.2 or 4.xx?

I have found that in my experience all these fancy blooming & 'A'rd to configure programs just quite simply DON't WORK or not easily.

Cheers,
Chris S

I cant upload hex files with arduino IDE and burning with atmel studio seems too complcted for me

I quite agree. Atmel have the programming power to make Studio 6.2 a sinch but

WHY DONT YOU DO IT MR. ATMEL?

Thank for replies. I dont know if flashing helped but I got it working however I think that the problem is in broken USB connector on arduino. I tried several cables and its working only sometimes with one cable but only in a particular position. So 16u2 has to be ok. I will try to change the usb connecotr.