If the 2nd card is not showing in Network Adaptors in the device manager (it might be as unknown PCI device in the device manager) then yes you probably need drivers for it.
Latest drivers are at
http://en-us-support.belkin.com/app/...a_id/542/p/200 please note there is more than once version V1 & V2 and the drivers are different.
The "unplugged" message though will still be your original card