Quoted:
The router is being used with a Bellsouth DSL modem. The router is configured properly, but it doesn't work when the computer is set to obtain an IP automatically.
I just re-read this... let me get this straight.... you have a second router in addition to the modem... so the setup is basically this
Internet=>dsl modem=>router=>computer in question....
If this scenariio is true, then.....
If you reset the dsl modem to factory the router will no longer work as intended as the modem will be trying to do dhcp and so will the router.... with this setup, you will not be able to "reach" the dsl modem to do admin thru the router and you will have to temporarily connect directly to the modem.... set the dsl modem in "bridge mode", disconnect and then set the router up to serve dhcp to the local net and enter/verify all of your connection info.... refresh ip on computer and you "should" be back on the air....
can you confirm that this is the setup you have, and if so, what dsl modem and what router are you using? There is more to this configuration than I have provided above, but more info would be necessary to go any farther....