What ISP Service do you have? Cable or DSL?
What ISP Modem do you have? Stand Alone or built in router?
What ISP Modem make and model do you have?
If this modem has a built in router, it's best to bridge the modem. Having 2 routers on the same line can cause connection problems.
What wireless modes are you using?
Try single mode G or mixed G and N?
What security mode are you using? WEP, WPA or WPA2? Preferred is WPA-Personal. WPA2/Auto TPIK and AES.
What wireless devices do you have connected?
Any cordless house phones?
Any other WiFi routers in the area?
Ensure DNS IP addresses are being filled in under Setup/Internet/Manual?
Turn off QoS options.
Turn off Advanced DNS Services if you have this option under Setup/Internet/Manual.
Turn on DNS Relay under Setup/Networking.
Setup DHCP reserved IP addresses for all devices on the router.
Ensure devices are set to auto obtain an IP address.
Set Firewall settings to Endpoint Independent for TCP and UDP.
Let us know.
I am having the same problem as the OP. It seems that every night when I get home from work I need to reset my DIR-655 to get the wireless working. The lights on the unit do not indicate an issue but none of my wireless devices pick up a signal. After resetting everything works fine and the next morning it is still working. Later at night I have the same issue again and today I lost the connection sometime during the afternoon while I was out. I have firmware version 2.00NA but when I do a firmware search from the router it says I have the most recent firmware version so I don't have the option of updating to correct my issue as the OP did. The only thing I should I mention is that everything worked fine for about a month and then once I installed a Canon WiFi printer last week this issue started happening. I don't know if it's coincidence or related. Can someone help me with this?