Naze32 board not connecting to betaflight or cleanflight. please help.

Hi, I have just bought a new board, connected it up to my PC, all works great. Tried to change some settings, all fine, then i pressed save and reboot. now my programme has stopped responding, the board wont connect to the pc and when i click connect it says "no response received within 10 seconds, closing port". Ive also tried to flash it back to Naze to reset, however no avail. Any help appreciated, thanks
 

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