problem with burning bootloader

[youceforo]

Hello,
I have used arduino uno in my project ,it was worked very well ,when I power on with Power Jack  ,it blocked and it was been undetected in my pc.
I tried to burn a bootloader using a working arduino as isp without succes and it appears this message:

avrdude: Device signature = 0x000000
avrdude: Yikes!  Invalid device signature.
         Double check connections and try again, or use -F to override
         this check..

please help,

[youceforo]

I found that problem is from the atmeg16u2 ,I tried to reset it but without succes ,how can I know if my atmeg16u2 is dammaged .

[johnwasser]

To re-install the firmware on the 16u2 you will need a supported ISP device.  I recommend that you invest $5 or less on a USBasp or USBtinyISP from eBay.  They will take a few weeks to arrive from the Far East but it saves a bunch of work when  you burn firmware or bootloader on a board with an ICSP header.  The USBasp is slightly cheaper but they seem to only come with 10-pin ICSP cables so they requires a 10-pin to 6-pin ICSP adapter to let you plug the 10-pin cable onto a 6-pin ICSP header.  The USBtinyISP may come with 6-pin, 10-pin, neither or both cables.

Notes:  
Change "-cusbasp" to match your ISP device.  
Change "-pm16u2" to "-pm8u2" if your board has the older chip.

Change Directory to the Arduino "hardware" directory.  

On Windows it is something like:
cd "C:\Program Files (x86)\arduino-1.6.13\hardware\"

On a Mac it is something like:
cd "/Applications/Arduino.app/Contents/Java/hardware/"

// MEGA update 16u2
tools/avr/bin/avrdude -Ctools/avr/etc/avrdude.conf -pm16u2 -Pusb -cusbasp -Uflash:w:arduino/firmwares/atmegaxxu2/arduino-usbdfu/MEGA-dfu_and_usbserial_combined.hex -Ulfuse:w:0xFF:m -Uhfuse:w:0xD9:m -Uefuse:w:0xF4:m -Ulock:w:0x0F:m


// UNO update 16u2
tools/avr/bin/avrdude -Ctools/avr/etc/avrdude.conf -pm16u2 -Pusb -cusbasp -Uflash:w:arduino/firmwares/atmegaxxu2/arduino-usbdfu/UNO-dfu_and_usbserial_combined.hex -Ulfuse:w:0xFF:m -Uhfuse:w:0xD9:m -Uefuse:w:0xF4:m -Ulock:w:0x0F:m