Grey screen… won't show actual lock screen

Hey guys I saw all of the help you guys give and I had to ask a question of my own. My itouch 4g will not show the unlock screen or anything except a grey screen. I know it powers on because my computer recognizes it and if I hold down the power button and swipe across the top of the screen it goes off (according to my computer or iTunes). I don't know if my home button is working because when I press it nothing happens, but when I press the power button briefly it comes on like if I wanted to unlock it. I was installing a new green screen and at first everything was working alright but now I don't know what to do. Before it wouldn't come on at all but then I grounded the battery and that got it recognizable by iTunes but that's all. Please someone help me I have a lot of stuff on my ipod and I can't buy another. At first it was a simple install I had hoped I would not mess anything up oh and btw it's jail broken