I would reset the router first.
That and update all the drivers. If your PC is not reading the Linskys card correctly your signal will be low at best. so go to Control Panel> Administrative tool> Device Manager> Network Adaptors to ensure the card is working. If it is and you still have no internet, try Network Connections to ensure it is receiving a signal. If not, reset your router and try connecting again... using a network installation disc if your ISP provided one, or manually using your network details/security key via Control Panel> Network and Sharing> Connect to a Network.
Hope this helps. 