I use a bluetooth headset. I tried disabling it, same problem. I am limited in where I can put the wireless router, but tried a few other positions nearby.
I've never had this problem with my actiontec router that had wifi that I used before I had to switch over to the modem/router combo with no wifi. I also have no problem connecting to the neighboring store next door's wireless router(they have the same actiontec router/dsl modem I used to have).
I have tried upgrading its firmware, moving it around, and went through the settings to disable the firewall, try G vs. N, try different channels, try it unencrypted. At this point, I'm left to assume it's a piece of junk.