-Thank you for your kind reply, err-Furry. Would you re-post that statement about "...except for either or or leaving it Auto...", please? It may be a typo, but it's confusing. In the meantime...anyone else with "INNN-put, i need inn-put" (-No.5).
-My DIR-615 reports that it has two devices internally, a 'GDI' and a 'router'...laughter met those revelations, since the little guy cannot seem to keep ANY of the 5 connections from one day to the next, using it's default settings [set via reset through the back hole for entire 10 seconds, with power adapter IN, and again, with power adapter OUT]. Doesn't matter whether the laptops are left on, with no sleeping allowed.
-One clue perhaps is that a (fully-up-to-date) Windows7 laptop, will obviously communicate with the DIR-615 immediately when W7 starts (watching with a monitoring applet), but seems never to get a Leased IP address, therefore no IPv4 access to www. [Our provider, like far too many, provides no IPv6 access, STILL, sadly. Perhaps on June 6th this year?] The previous occurred when using WPA-2 Personal Edition connections (and when two other laptops were working quite nicely).