Try going to your command prompt and type ipconfig /release_all
and type ipconfig /renew
If that doesn't work try this.
Go to the control panel, fine network connections, go to the local Area network. Rigth click and go to properties, scroll to Internet Protocol (TCP\IP) and double click. Fill in the IP address, subnet, gateway and DNS.
Go to a PC that is working and get the IP settings from that to enter in the setting for the computer that is not working. However, with the IP address of the computer that is not working make sure u you an IP address that is not being used.