Thanks. Worked for me as well. 2 weeks after getting watch display went out. Watch was working; confirmed by app on phone being synced and updating properly. Could turn watch on and off; confirmed by watch vibrations and blue tooth connection with phone (connecting/disconnecting when watch turned on/off). I tried holding power button down while on charger a couple times before finding your post but I only held the power button down for about 10 to 15 seconds each try with no result. After reading your post I tried again but holding it for as long as it took. After about 25 seconds display came on with the message watch rebooting. Thanks again, saved me a wasted trip back to the store.
Unfortunately I dont seem to be as lucky as others in getting this issue fixed. Had the black screen for nearly one week now. Tried the suggestions that have been posted, including holding down the power button for at least 2mins. Sometimes feel the watch vibrate and connection/disconnection notification on the app appears. Battery was showing as 86% on the app, now down to 2% so something is going on on the background. Any help or suggestions would be greatly appreciated.
Still no joy trying that. I uninstalled the app and installed again. The watch vibrates and the app says it can find the watch via bluetooth however still a black screen. Driving me nuts this!
Same problem but the power button didn't work. While on the charger I pressed the reset button and held it. It's at the 5 o'clock position below the power button.