Wtf at my ipod touch :/ It shows sign of jail breakage.. yet I've never jailbroken it :l?

Like I can't reset it ever because the power on doesn't work , only once in a while i hit the right spot and it goes off. Other times ... just no. Like five mins ago I decided I was gonna watch a movie on youtube via my ipod touch. I turned it on and it didn't turn on cos' it was flat so I put it on my alarm clock dock and the screen went green I started to panic so I googled it and was confused when answers claimed that this happens after the ipod is jailbroken or when its in water. I haven't got any water on it, or jailbroken it. But at school the other day I dropped it on the screen it didn't scratch nothing happened? I didn't wanna use it in case but my friends kept hling me to play it. I then realized I hadn't even tried to push the home on after I saw the green screen ,I pushed it and it's back to normal now. It's now charging But wtf ? Can someone tell me what just happened.. :/ I dunno if it will happen again..only time will tell but I'm scared cos my warenty ends like in a week or something. Its a 2nd gen, do u think the droppage afftected it. =) Answer pls! I'll give my 10 pnts to an explaination and some advice:Do you think I should take it back to the shop ? What do I like say bah ? :)