I put my Vita on hibernate last night, by pressing the Playstation button, then tried waking it later on, and nothing happened. I thought maybe it was the battery (it was pretty low just before I turned it off), so I put it on charge overnight. The PS button glowed orange, and in the morning it wasn't glowing. Full charge, I guess.
Pressed the power button: nothing.
Pressed the PS button: nothing.
Pressed the power button for 30 seconds: nothing.
Pressed the PS button for 30 seconds: nothing.
Pressed the Power and PS buttons for 30 seconds: nothing.
Pressed the Power, PS, and R1 buttons for 30 seconds: nothing.
I also tried all of the above with the memory cards out, just in case, and still nothing. The only thing I can think of that I haven't tried is turning it on while it's on charge, but I can't try that until I get home. Anyone got any other ideas, or shall I just return it to the store? :\
edit: If it helps diagnosis/opinion; I've had the Vita since Feb 29th, and I've never had a problem until now.
The fact that it won't turn on even after following reset instructions sounds as though a component has failed. That's pretty unlucky but you're well within warranty and probably your Stores refund period. Take it back and get another