Sony Xperia U Broken?

[Whizawk]

I have had my Sony Xperia U for two weeks now and it is refusing to turn on.

I left it on charge overnight (I don't know if that's harmful) and I woke up in the morning with it fully charged to 100%. I only made a couple of phone calls during that day and in the evening I found it to be off, which was odd. So I tried turning it back on and it wont respond, the thing seems as if it is completely dead.

I only charge the phone via the AC plug and never with USB.

Like I said I haven't really had the phone for long and it's broken already.

[Whizawk]

I've managed to fix the problem. I had to take the battery out for awhile and put in back in the phone and stick it on the AC charger.

???