Hi Jayne.
Looks as though your new laptops network adaptor sees the wireless router downstairs as your network lists as available.
You need to make sure that the laptops settings are identical to those of the router.
Ensure that network sharing is enabled on the laptop within XP and that you have the same 'workgroup' name set as the router and PC downstairs.
If you have secured your WLAN (which i hope you have) then obviously the Encryption key needs to be identical and you will also need to list your laptops MAC address in the routers filter table if you have MAC filtering enabled on the router.
To set or change workgroup names in Windows XP, right-click on My Computer or open the System icon in Control Panel, then choose the Computer Name tab and finally, click the 'Change' button to access the workgroup name fields.
Here is a great tutorial on
setting up your home wireless network correctly.
http://www.microsoft.com/windowsxp/u.../wireless.mspx
Its very important that you secure your wireless network as you state that you can see 2, sometimes 3 other networks close by and if you can see them, they can see you (unless you have broadcast disabled on the router) and if your not secured, they can hook to your network and use your internet bandwidth and most probably share resources which means access to your computers on the network.
Securing a wireless network:
http://www.practicallynetworked.com/...ess_secure.htm
Good Luck
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