Using AX as wireless router, how to set up w/ security and airtunes on XP

Question

I previously had a Linksys wireless router. I just purchased an Airport express to use as the wireless router (and remove the Linksys router) as well as use the Airtunes functionality.
After some trial and error, I have been able to wireless connect my computer to the AX on it's own (the linksys router is now unplugged and out of the equation). I can connect to the internet fine on my PC (XP Pro SP2).
Trouble is, when I use the Network Setup Assistant, it shows the apple network listed, but it can't connect to it, no matter how many times I try, reboot my machine or reboot the AX. I've tried both the "setting up a new network" and "editing an existing network" option, and in each selection, after a few minutes of trying to connect to the network, I just get a failure message.
If I try and use the Admin utility, nothing shows up in the left-hand list window, and when I Press re-scan, still nothing shows (it doesn't even appear to scan).
I'm not sure what I'm doing wrong. I can't find simple instructions on how to set up the AX as the only wireless router for a PC and set up security and Airtunes (I'm assuming enabling airtunes is done in these applications, as I haven't seen anything about that yet either).
Any ideas on how this is done with a PC? Much thanks!
Dell 4500 series

Answer 1

I have found the 'DHCP Reservations' option on the AirPort Extreme to be buggy.  I seem to remember it causing IP conflicts for some reason.  I think what I remember is that if the computer with the reservation was off, and the DHCP server then handed out that IP to another DHCP client, then there would be a conflict when the reserved IP computer was turned back on.  Maybe it was an issue in ealier versions of the AE or OS X as the case may be, and maybe it's been corrected, but I've never bothered using it agian since the method I describe below has always worked without fail.  Also, I'm guessing DHCP Reservations would work fine if one manually enters IPs outside of the DHCP range but in the AE 'DHCP Reservation Setup Assistant' the IP options provided are within the DHCP range which to me makes no sense and increases the potential for IP conflicts.
Here's what I do to setup a mixed environment of static and dynamic IPs on my network.  It works like a charm and does not require the DHCP server (beyond the distribution of dynamic IPs to hosts using DHCP).
For machines on my network that are accepting services from the public network, I set them up with static IPs using the 'Manually' option (System Preferences/Network/Ethernet/Configure IPv4).  The settings for 'Router' IP address and 'DNS Server' IP address should both be set with your gateway/router LAN IP).  Use an IP address below or above the DHCP range of adresses (in AE/Internet/DHCP/DHCP Beginning & Ending Address).
i.e. if my subnet is 10.0.1.1 and my DHCP range is 10.0.1.100 to 10.0.1.150, you could set the static IPs on your local hosts as 10.0.1.x where x = any number from 2 - 99 or from 151 - 200 as an example.
All other machines and devices that do not require static routing are setup as DHCP clients and get a dynamic IP from the AE.  To me it's a simpler setup though it might take a little extra time to setup initially.
John