How to connect power-off watch to pc

[Smith 001]

Hello,today I want to flash my watch,but I found that pc could not recognize my watch when it is power off.
My watch could be recognized when it is power on,I can access it.But when it is power off....
It seems like the watch is dead.....:'(
Any suggestions are appreciated.Thanks!
BTW:my watch os is Android 5.1.

 

[Rukbat]

If it's not running, there's no activity on the data wires, so there's nothing to recognize. Charge it until it powers on. (If that's not the problem, it needs a repair shop.)

 

[Smith 001]

Thanks,but flashing a firmware needs my watch to be turned off.And I drained out its battery,then I plugged my watch to pc.But nothing happen,I can't flash it.

 

[Smith 001]

Hi,a friend gave me a suggestion.But after everything done,I still can't flash my watch.
I opened device manager,selected portable device and found my D5+ below.
And UPDATE it without any issue but when I shut down my D5+......Nothing shows on my computer.