Need more information. What router are you using? Are you talking about just
good signal strength or can you actually connect (i.e. view files) to your
other PCs? Do you get an error message when the connection fails? Can you
access the wireless router's setup screen from the Vista laptop? If you
bypass the router and plug the Vista machine directly to the broadband modem
(I'm guessing at your type of internet connection) will it connect to the
internet? Is the Vista machine set to use DHCP? Does the Vista machine
appear in the router's DHCP table? Have you configured the Vista machine's
wireless security properly?
The more you include about your enviroment, the better the chances are at
solving the problem.
Tim