[caph]

To remove the network as Jellybaby says you need to go into Control Panel -> Network and Sharing Center (US bad spelling!), then click on "manage wireless networks" the click on the SSID in question to select it, then click on the remove button at the top of the screen. Then you should try and connect to the SSID again and it will ask you for the password. If you keep getting this then there is another problem. I have Vista and the only time I get the problem you describe is when I change the wireless security settings on my router.