What wireless modes are you using? Under Setup/Wireless/Manual.
Try single mode G or mixed G and N?
Be sure to change the SSID name to something you can recognize easily. There maybe other WiFi routers with the name dlink.
What security mode are you using? Try turning OFF wifi security as a test. 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.