Airport Networking Problem

[bjscully]

So, I have two Windows computers, one laptop and one desktop. The desktop was on a wireless connection and I could share folders and files. But once I moved my set up to help the desktop internet connection speed, I can no longer see either machine from the other one. I can ping the Airport extreme and the WDS connected Express, but not the IP of the other computer. Anyone have any ideas why this might happen? I used to use Linksys routers and their networks simply communicated.