Dell TrueMobile Series 1150 wireless miniPCI card cannot connect to WiFi network, W2k

I recently installed a Dell TrueMobile Series 1150 wireless miniPCI card (driver version 7.44) in my Latitude C800 running W2k SP4. (By “installed” I mean replaced the cable modem card in the bay under the laptop, and connected the antenna connector to the laptop connector and corner card connector.) I also installed Dell TrueMobile Client Manager v2.58. When I loaded the Client Manager, I left the Network Type as Residential Gateway (not Peer-to-Peer), and input the network name: HOMEOFFICE and the wireless key for WEP.  

Unfortunately, I cannot get either internet connection or file sharing via WiFi. 

Client Manager recognizes the wireless network: “HOMEOFFICE”, with Radio connection: Excellent, an Access Point name, Channel: 1 and Encryption: On. However, Control Panel/Network Connections shows the TM 1150 as “Network cable unplugged”. Its Properties show as checked: Client for MS Network, File and printer sharing for MS network, Pure Networks Device Discovery Driver, Pure Networks Wireless Driver, NW Link Net BIOS, NW Link IPX/SPX/NetBIOS Compatible Transfer Protocol, NetBEUI, Internet Protocol (TCP\IP) – in that order. The Wireless Configuration service is set to Automatic, and is Started. 

I tried using NetMagic on this laptop, but it didn’t recognize the WiFi network atall. 

On my other (XP) laptop, internet connection and file sharing both work through WiFi, using WEP, via my Netgear WiFi router. My router Wireless details are SSID: HOMEOFFICE, Channel: Auto, Mode: b and g, Security Option: WEP, Authentication Type: Automatic, and Encryption strength: 64 bit. 

Am I missing some software or settings to connect this m/c to the WiFi network?