Thank you very much Al. Since posting I have discovered some of the things you said. Basically the problem had to do with IPs being in different ranges. Thanks for the help.

Alex

>If you ran some software on your PC (to "configure" the wireless router), while the router was between it and the firewall/switch, that software may have reconfigured your PC's network connection to work with the wireless router. The router's LAN settings are probably different from the Watchguard's.
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>By default, Windows XP computers obtain network settings automatically from a DHCP server. Maybe that has changed on your PC.
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>From a command prompt, run the following command on your PC, plus one of the other ones it can't currently see, and post here the results of ipconfig.txt:
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>ipconfig /all >c:\ipconfig.txt
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>A few other things to think about:
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>- ideally, in your situation the new Cisco wireless router should be configured as an access point, rather than the (almost certainly default) router mode. If set up as a router, you would need to make sure that its LAN subnet is different from the Watchguard's. Also, the iPad and Kindle would be able to see the computers on the LAN, but not vice-versa. When configured as an access point, you can think of the device basically as attaching a wireless switch to your network.
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>- if you leave the wireless router in router mode, you can leave its default DHCP server enabled, but if you switch it to access point mode, you must disable the DHCP server (assuming that the Watchguard already provides one). You can't have two DHCP servers on the same subnet