Dlink router wireless. Problem getting IP addresses

I have a dlink dir 615 router. I have two Win 7 desktop PCs connected to it by LAN, and an xbox, an iPhone 4s, and an HTC Evo 3d regularly wanting access to the WAN (there are other devices, but these are the ones that use the wireless signal regularly). I usually have to reset the router at least once per day so that I can restore the wireless service. My HTC can't seem to obtain an IP address when this happens, and of course, none of the other wireless devices in the house are able to connect either. Once I have reset the router, wireless access is restored... for a while.

I have run antivirus, I have set encryption on the WAN to WPA-personal and have DHCP enabled.

Thoughts?