iPod doesn't turn on ... I have to plug it in the PC

Hi guys
This is my history with my new iPod nano.
When I got it, all was fine. One day, I decided to install the iPod updater. iPod Updater 2006-06-28

After this, all the problems begun. I had to format it with the HP usb formatting tool, then to run the updater again, and well, now it seems to be working again, but:

When I arrive home, I turn off my iPod by holding pause button for 3 seconds. The next morning, it is impossible to turn it on again... it seems that lot time turned off makes it to be dead... I have to connect it to the PC for it to wake up. When I connect it to the PC, the apple logo appears, and then it turns on again...

Does any1 have an advice about this ? What would you recommend to do ? ipod nano 4gb black

Thanks.