WiFi Disconnection Problems

After searching the internet last night for about 4 hours and trying every possible solution I can find, I'm still having the same problem. I thought posting my specific details might help.

Every 5 to 10 minutes, my MBA "seems" to disconnect from the internet, although according to my Mac, it's still connected and shows my current IP address. I know it's not my router (Dlink DIR-624) because everything else stays connected. I don't have a problem with my Dell laptop, AirPort Express (used only to stream iTunes to my home theater), iPod Touch or either of my iPhones. The problem only occurs with the MBA.

Renewing my DHCP Lease fixes the problem for a couple minutes, but then I lose connection again.

Here is what I've tried so far:

-Installed all updates
-Repaired disk permissions
-Updated router firmware
-Turned off IPV6
-Assigned static IP address to MBA
-Moved from WEP to WPA and then to WPA2 encryption
-Changed router channels multiple times, from 6 to 9 and then 11
-Deleted and recreated all keychain entries related to my wireless network
-Changed keychain entries to "Allow all applications to access this item"
-Removed all saved networks, except for my home network.

I've read that you need to remove RealPlayer Updater from the list of Login items, but I don't seem to have that installed. At least not that I could find.

This is driving my crazy and any help would be appreciated. Thanks!

I ended up getting my problem fixed.

I read on another forum that the Airport express "has problems" with older routers. I'm guessing that conflict was causing the rest of the network to become unstable.

So, I purchased a DLink DIR-625 from Amazon for $54.99 and that solved the problem. Everything has been completely stable for the last two hours. I have the MBA, two iPhones, one PC, an Xbox 360, Airport express streaming iTunes and my ReplayTV all running at the same time with no problems.