:highfive: Finally got the 4.3 updated to my Gnex.. Cured all the problems.. Guys for the ones who faced the same problem...Let me help you.
1. Go to the bootloader assuming that you followed all the steps i.e of unlocking the bootloader & rooting your device thru this wonderful tool (Long press power key & volume up & down key simultaneously).
2.Unplug the USB cable and re-plug it again.
3.Go to MY COMPUTER>DEVICE MANAGER> ANDROID> Now right click on the driver and uninstall it..You will be prompted whether to delete all files fr this driver...Press yes..(please make sure you remove all the ADB drivers installed)
4.Now follow step two again.
5.Windows will manually install ANDROID 1.0 i.e ADB interface.
6.Go to the tool press option 9 & let tool do his work..
Tool will update your phone ,it would take round about 15-20 min maybe even less then that.. A FRESH NEW LEASE OF LIFE TO GNEX.... Thank you very much MARK for this wonderful tool & NCguy - for taking time out n replyin to my post.. Much appreciated.
HIT THANKS, IF I HELPED YOU.. CHEERS ..WISHING YOU ALL A MERRY CHRISTMAS & A HAPPY NEW YEAR...:good: