What region are you located?
Are you wired or wireless connected to the router when the TV, Belkin USB adapter and DirecTV?
Check to see if the modem has a DMZ option and input the IP address the DirecTV unit gets from the modem and put that into the modems DMZ.Setup DHCP reserved IP addresses for all devices ON the router. Setup/Networking. This ensures each devices gets its own IP address when turned on and connected, eliminates IP address conflicts and helps in troubleshooting.
Ensure devices are set to auto obtain an IP address.
Try disabling the Firewall as a short term test to see if this effect any thing.
What wireless modes are you using?
Try single mode G or N or mixed G and N?
Channel Width set for Auto 20/40Mhz or try 20Mhz only.
Try setting a manual channel to a open or unused channel. 1, 6 or 11. 11 for single mode N if the channel is clear.
What security mode are you using? Preferred security is WPA-Personal. WPA2/AES Only. Some WiFi adapters don't support AES, so you might want to try TPIK only or Auto.
Any other WiFi routers in the area? Link> Use InSSIDer to find out. How many?Enable
WMM Enable if you have this option
urn off all anti virus and firewall programs on PC while testing. 3rd party firewalls are not generally needed when using routers as they are effective on blocking malicious inbound traffic.