What Firmware version is currently loaded? Found on routers web page under status.
Try single mode G or mixed G and N?
What security mode are you using? Preferred security is WPA-Personal. WPA2/Auto TPIK and AES. Some WiFi adapters don't support AES, so you might want to try
TPIK only.
Any cordless house phones?
Any other WiFi routers in the area? Use
InSSIDer to find out.
Turn off Short GI and Extra Wireless Protection if you have it. Under Advanced/Advanced Wireless.
Put the MC in the DMZ. I have one as well.