Linksys E1000 Router - Network Adapter Can't Connect To Router

One day I got a blue screen saying there was a hardware or driver failure with the network adapter on the motherboard. I couldn't resolve the problem so I went out and got a new network adaptor. Pluged it in, windows found drivers for it. But I was getting a Unidentified network problem.I have a Linksys E1000 router, internet works on my laptop and xbox360 fine wired and wireless. So I changed ports on the router, changed cables, even changed routers. Still the PC wasn't seeing the router. So I download the latest drivers for the Realtek network adapter, install them, still nothing. So I thought maybe the router is to blame, downloaded the latest firmware and flashed it onto the router, reset it. Still the same. At this point I was sure the new network card was faulty. So I took the computer to the shop where i bought the card. He disabled the old network adapter in the bios. And he had the Internet up and running in the shop. I was happy and took it home... Still the same problem! Rang ISP done a lot of disabling, enabling, static IP no fix... except he told me to bypass the router and try plugging the PC directly to the modem, and that connects fine. I can get internet from the modem, but not through the router, yet everything else works fine though the router. As I said cables and ports in the router have all been changed and checked. When I do the network diagnostics in windows 7 is says, does not have a valid IP configuration.