Just wanted to post as I nearly just threw my watch away...
tried 'solution' on this post - nonsense.
My solution: just let it loop and keep it plugged in.
When the device was looping it was actually very slowly charging, just left it on to loop 50+ times and now it turned on. Must've just had a really dead battery or my plug is not providing much current. Anyway, don't have to shell out on another watch now!