[L520] Stuck on lightning bolt and gear?

[WPCentral Question]

i switched off my lumia 520 and when i turned it on the lightning bolt and gear image and since then its not responding or going any further...

 

[Ed Boland]

Plug the charger in and restart it. (hold power and volume down buttons together until it vibrates)

 

[Daryl Duke]

its still not responding after doing so. actually its not vibrating at all, it just switches off.

 

[Suicide Stacey]

Hard reset it is then....volume button up and power button...bit you will wipe all your data tho