Problems with Ethernet Connection

[Gargleman]

I am having problems connecting to the internet. I have a computer upstairs hooked up to my dsl modem and a D-Link router hooked up to that, from which I have an ethernet cable hooked up down here.

Now the problem basically is that I am able to go online some of the time, but sometimes it tells me the page cannot be displayed on Firefox.

[molotov00]

It's a shared connection? Or is your modem connected to the router?

When this happens, are you able to ping the upstairs computer?

ping <hostname or ip>

When this happens, are you able to access the internet when using the upstairs computer?

[Gargleman]

the modem is connected to the router.

I haven't tried pinging it, which ip do I ping for my upstairs computer? Its running on Windows Xp btw.

[molotov00]

Try xp computer and router.

[superprash2003]

try changing DNS servers to opendns - 208.67.222.222 and 208.67.220.220