My Iphone 4 screen went grey & has been stuck like that for hours

My phone screen went grey & I tried restarting it & nothing is happening. I know they usually restart themselves, but it usually doesn't take this long. My friend suggested waiting until it dies completely & then when I charge it, it will come back on. Does anyone else have any other suggestions?

You must have dropped it at some point in time. The same thing happened to my friends phone and she went to get it checked out. It was broke and she had to get if replaced. Also, if water came in contact with your phone, that could've caused the problem.