need help w/ d-link router setup!!!

hello,
I am having a hell of a time connecting a d-link router to add second computer to my dsl setup. Here’s my setup:
2 pc’s
dsl modem (2wire)
d-link router
Here’s the thing, I setup router settings accordingly for dsl modem and everything worked out fine, both pc’s had internet, then 1 hour later, nothing!!! So I’ve tried the settings again over and over and nothing. I have not messed with the cable modem settings, so don’t know what could be the problem? I connected the modem w/o router to make sure modem is working which it is as well as the router.

thanks for anyone that can help
dan