Turn off ALL devices accept for one wired PC.
Open the routers web page and go to Setup/networking.
Ensure the one wired PC is reserved for an IP address. Save the setting if you need to.
Not turn on the next device and let it come to ready.
Do the same thing and reserve the addresses on the router. Save settings.
Keep doing this for each device.
For your wireless devices, make sure you care connected to your SSID name.
Change the name of the SSID name under Setup/Wireless/Manual. Default is dlink. There maybe another dlink router near by that your accidentally connecting too. So change the name to something you'll recognize, can be anything, make it something fun.
ry single mode G or mixed G and N?
What security mode are you using? Preferred security is WPA-Personal. WPA2/Auto TPIK and AES.
Any other WiFi routers in the area? Use
InSSIDer to find out.
Maybe someone can review your router settings with you using
teamviewer. If needed.