ipod does not connect

[leylo]

I purchased my ipod nano through ebay, unfortunately it did not come with a charger or software installation cd. All I have got is the ipod itself and a usb cable.
When my freind takes it to work it charges through USB port, however on my or my sisters pc it does not connect at all, it does not show up in "my computer" or in "device manager" and also doesn't connect to "i tunes 7".

The weird thing is when i first got the ipod, it connected to "itunes" and transfered my music accross. Now it does not work at all.

I am stumped! any advice would be much appreciated, thanks.

[cjmnews]

iTunes 7 does not recognize iPod: http://docs.info.apple.com/article.html?artnum=304434
iPod does not show up in My Computer: http://www.info.apple.com/kbnum/n61711
iPod is in My Computer not iTunes: http://docs.info.apple.com/article.html?artnum=93716