things to troubleshoot. It can be ANY of these below.
protocols on PC, network card, cable from network card to wall jack, wall jack to patch panel, patch panel cable to the switch, port on the switch, server on the network.
PC PROTOCOL
Make sure you can see the network, if your using tcp/ip, try to ping the server, make sure you have an address, if using DHCP, make sure dhcp server is running.
Network Card
You checked this already.
cable from network card to wall jack
You checked this already.
wall jack to patch...
Try putting another computer at your location, and see if it can get on the network. If not it may be the cable run from the jack to the patch, patch panel cable, or port on the switch.
server on the network
If you do have an IP address and you can ping mosts hosts, then you shouldnt be the only one having a problem. Call your Admin