I have somewhat the same problem that has been bugging me for quite a while. I am connected from my laptop via wirelss to my DLink (OK I know, I know) wireless router and every day or so it will all of a sudden just drop the ability to connect to the wireless part of the router while the 4 port wired connections hum along just fine. I try to “Repair” the connection from my laptop but it can never obtain an IP address after the “drop”. I have to power off the router and power it back on to re-establish the wireless connection then it’s fine for a couple of hours or days. I had this same thing happen with my previous Netgear router.
Any ideas?