It is hard to keep it on to do much troubleshooting as it is a very big issue to other users connected to the router.
hmm dlink--- g wireless..
not possible to use third party firmware such as dd wrthttp://www.dd-wrt.com/site/support/router-database
seriously you should consider some other good and may be cheap wireless router.
Asus RT N12, may be
Here is what I think, a wireless router should not be reset because of any client , even the clients misbehave! unless its client happened to be the admin and he log in to admin page and reset the router.
One thing you could try:
just use wired LAN, and see if such behaviour persists.