Well, I've been pulling my hair out trying to deal with my Windows 8.1 PC on my network. Everything worked perfectly fine with connecting to my Airport Extreme network under windows 8. I "upgraded" (going to use that term very loosely at this point) to 8.1 from the Windows Store and now network accessibility has been shot.
At first I thought that my Cisco AE2500 adapter was incompatible (according to Microsoft's website, it is NOT compatible with Windows 8.1) and so I went out and purchased a Netgear N300 (which is listed as compatible with Windows 8.1), but still have the same issue. I can connect to my network, but my Windows PC is not receiving an IP address, etc.
Now I manually configured my Airport Extreme to force an IP address on my Windows 8.1 machine, and I've got small bits of network access -- I can browse the web, start a service like Steam. Ironically, however, I can't access with Windows Store or Microsoft Update. Also, I can't "activate" Windows (why I would need to "active" it again is completely beyond me). I think it has to do with some botched network installation on the upgrade. When I try to view the networks by right-clicking on the Wireless icon in the task bar, it says "The dependency service or group failed to start" where the networks should appear (see the attachment).
So far not impressed by any means.