Ipod not found by itunes

my 4gb ipod nano is not seen in itunes so i cannot
restore it back to factory settings. I have done the
5r's resetting it putting it in disk mode,
reinstalling itunes everything. I downloaded ipod
updater software but it says that I MUST use itunes
and stops running. I cannot restore my ipod without
using itunes but itunes dosent see it. My ipod is
found in my computer and the ipod itself seems to be
working but I think the ipod lost some files itself.
How do I get around restoring it??!!! i tried using
my sons ipod and itunes sees it no problem and works
great. also when i plug my ipod in itunes starts
but never shows the ipod in devices.

acer 7100 Windows XP