Hello;
I to had the same problem with my Dlink WBR 2310. It would disconnect during downloading or when another computer logged into the network or when it was raining.

But I found a rock solid solution.
The solution that worked for me.........updated the DLink WBR 2310 with DI-624 firmware version 4.04 dated Mon, 14 July 2008.
That was one month ago with no resets!!!!!!
I would recomend this upgrade to all.

You'll find the DI-624 firmware here:
http://ftp.dlink.ru/pub/Router/DI-624/Firmware/Rev%20D/
(save the file that ends with ".bin".)