Help setting up ethernet

I've been trying to set up my Mum's eMac for the past hour... but I can't even connect to the router, let alone the internet! I know the subnet mask and I know the router address and the IPs between 192.168.0.100 and 192.168.0.199 are enabled... but it won't connect automatically and it won't connect manually...
The cable is connected properly and everyone else on the network is connected fine. I can't even access the router by typing in the router address in Safari...

Where am I going wrong?

What brand and Model is her router? Does it have status lights on the router? Does the light for that port light that the EMac is plugged into?

Also what version of OSX is on that Emac? Are you sure the Ethernet cable is wired correctly and working?

Sorry, been kinda busy.

The router is a DLink - the status light corresponding to the port is not on when the eMac is plugged in. So I assume it's a problem with the cable... when I get one, I'll try a different cable and report back...

For sure report back. I have seen a few posts here and there where some router would not work with an older Mac with no light on the router when the cable was plugged in. I have a couple of older Dlinks here and they work with my old iMacs. I hope it's the cable. If not do check the RJ45 jack on the EMac. I have seen some of the similar iMacs where someone crammed in a RJ45 plug and bent pins in the Jack on the Mac. Just bending them back solved it and got them a light.

has this ever worked? Does it work when you use a static IP? Does it work when you boot off the install DVD and go to test utilities?