Vista wired network problem

I cant figure out why my Vista Ultimate computer will not connect to my router. It is connected via lan cable. Even after reformatting it would not connect to the router and the weird thing is that the router doesn't even know it exists when I bring up its client browser from a different computer connected to the same router. The connection light is on signifying that the cable is connected and data is being transferred but, my guess is that something is wrong with my onboard lan connections on my motherboard. I was hoping maybe i did something wrong to create this problem. If anyone knows how to fix the issue i'd greatly appreciate it. I have already tried all the basic troubleshooting techniques like unplugging both my dsl modem and router for 30 seconds - 5 minutes, configuring the onboard lan to 100full duplex, disabling and reenabling connections, reinstalling drivers, reformatting the entire os, manually setting the ip address default gateway ect, and even buying a new lan cable. help!

make sure your router has dhcp enabled and that your network card doesn't have a static IP.