
   D-Link, please address this problem.  Similar dropouts have been described in several posts!!!  
I have what is apparently the same problem.  Let me add my details:  
•   I have DIR 615 Rev C1, Firmware 3.11NA.  It was purchased in December timeframe.
•   I am networking a Win7 machine and a printer via cable, and with 2 WinXP machines and a PS3 connected wirelessly.
•   Often the machines show up as available, but when I try to open them, none of the shared folders can be found.
•   Sometimes, I can’t even open the shared folders on the hard-wired computer, and sometimes it doesn’t even show up as there even though it is the computer I am using.  Even under that condition, I can usually access the internet.
•   This happens to me about once every couple of days.  
•   Sometimes I lose the internet connection as well as the home network.  When this happens, I can bypass the router and see the internet.
•   I also have a cell phone and 2.4 GHz home phones, but interference would probably not explain my losing the cable connection.
•   I am set up with fixed IP addresses to the router and I have them reserved, but my internet connection is DHCP.
•   Power-cycling the router and cable modem and rebooting the main computer always fixes the problem, but I haven’t yet been able to pin down which of these things is necessary.  Once I “apparently” fixed the problem by just logging off my main computer, and then back on again -- but I know that doesn’t make much sense because it shouldn’t affect the wireless connections.