nRF51 board flashing green light

[refdaddy]

Plugged in board to Win 10 pc that was working properly in past. Start NRF tools and get error.....

ERROR Unable to read connectivity firmware version: Unable to get version info for 681408717: Error occured when get device info. Errorcode: CouldNotOpenDLL (0x7) Lowlevel error: JLINKARM_DLL_NOT_FOUND (ffffff9c)

re-installed updated app and chose com port (showed proper board serial number) and error msg repeats

pressed reset button and connected power from usb.

My board will no longer connect and green light is flashing. When I first connect there is no light. Light only starts after I apply power and then depress reset button.

Any ideas?

Thanks

[refdaddy]

my board was working before with windows nrf connect. now when usb cable is attached and nrf connect program started, the green light on board is dark and I cannot select com port to connect.

I had another problem earlier and I tried to resolve it by pressing the reset button on nrf51 board during power up.

Do I need to re-flash the board's firmware. If so, please point me to instructions

Thanks