Hi and welcome to Aximsite. Lots of good info and ppl here.
A few things you can try:
1. Make sure the battery is fully charged. (Flashing yellow means the battery is low)
2. Press and hold the power button
3. Press POWER + RECORD buttons at a time
If one of these don't bring the display back, you may need to do a hard reset. (last resort) :(
Hope this helps. :)