Hard-wired connection cannot work on Dlink DSL-2640T

the wireless connections work fine...but when I connect the ethernet cable, the hardwired connection cannot access the internet. am I supposed to tweak any settings to make this work?

We're probably gonna need a bit more info mate, have you checked wether you have an IP set on your Local Area Connection? That's probably the most likely cause, followed by a bad ethernet cable, or a bad network card, or even possibly a dead port on your modem.