Try the following:
Open up your Control Panel, and double click on the 'Network' icon.
Click once on "Client for Microsoft Networks" in the next window, and then
on the "Remove" button.
You'll need to reboot once the listing is removed, but the Windows password
prompt shouldn't show up again ... NOTE: This is going to remove the Network
Neighborhood icon from your desktop. If you need to set up a home network
at a later date, you can add the MS client back in through the Control
"Don't know if that will do it" but worth a try