Problems with iPod Nano 4th Gen

Hello Friends,
I've two iPod Nano 4th gen (8GB). I'm facing a severe problem with both of them. For both iPods, I tried to do this method Simultaneously press the top button + home (central) button. But of no use.

1. My first iPod is showing a white screen. I could not see anything. But I can listen to songs by blindly pressing the play button twice. The battery comes only for an hour.? How do I get the display and longer battery?

2. My second iPod is facing more severe problem. None of the buttons are working. When I connect it my PC it showing "CONNECTED- eject before disconnecting". But it is not ejecting with all the usual methods. When I manually and physically disconnect it from the PC the same "CONNECTED- eject before disconnecting" is still showing till the battery goes off. After that if i press any button it is showing low battery signal. And when i re-connect it to the PC the same process is repeating. When I tied to restore it to the factory settings I'm getting "Error" report. (I'm using windows 7)

Friends, Please help me with the above problems. It will be a great help.
Thank You.

R.SAMALA