Vista laptop connected to Home Network with W98SE and 95

>I have just purchased a HP DV9330 lap top with Vista Ultimate installed and
>NIS 2007.
>I already have a cabled home network for my Dell Dimension XPS T600r PC
>running 98SE, and an older Compaq Armada 1500 series lap top running 95,
>which work through my D-Link DI-604 Broadband Router to my Motorola cable
>modem to the Internet and each other.
>I can access the Internet with my HP laptop, but cannot see the other PC and
>laptop with the Network Map. Also I don’t see the HP connected when I check
>Network Neighbourhood on the other computers.
>Even if I type \\computername in the HP laptop Network icon address bar I do
>not see either computers.
>The HP laptop Network Discovery is turned on.
>The File sharing and Public Folder sharing is turned on.
>I have all the computers set for file and printer Sharing for Microsoft
>Networks.
>The Windows firewall is disabled.
>
>Would the NIS firewall settings be incorrect or is there some other setting
>I should be looking at on the HP laptop, D-Link Router or older PC and laptop
>Network Neighbourhood?
>Any suggestions would be appreciated.
>Thanks,
>Bob