And hopefully this will be my last reply to my own replies :emotion-5: I think I have accidentally discovered how to give control of the wireless network back to the WLAN card utility software.  What I did was this:   Opened the "Dell Control Point" software. Selected "Connection Manager". Clicked on the "Connections" button. Selected "Profiles". Selected "Change Settings". Selected "Program Settings". This displayed a dialog with a group named "Available technologies" that contains 5 check boxes (Ethernet, Wi-Fi, Mobile Broadband, Dial Up and GPS).  I then deselected the Wi-Fi check box. This then disconnected me from the internet (as expected) but then when I opened the WLAN card utility software the option to "Let this tool manage your wireless networks" was enabled and I could successfully add (and manage) my wireless network using the WLAN utility.  Hurrah!   Phytorian, try these steps and hopefully you'll have the same success as I've just had! I've now got a bottle of wine with my name written on it... :emotion-2:      
I've just had to install a new hard drive in my Latitude E6400 and have reinstalled Windows XP and all the drivers / software from the dell downloads website. When I run the "Dell Wireless WLAN Card Utility" application on the "Wireless Networks" tab the checkbox to "Let this tool manage your wireless networks" is selected but greyed out.  Also, all of the options in the "Preferred network connections" (i.e. Add, Edit, Remove, Up, Down & Options) are greyed out as well so I can't add details of my wireless network.  How do I go about enabling these options?  Is it a driver issue? I can connect to Wi-Fi if I configure the network via the Dell Control Point -> Connection Manager software but I'd prefer to use the Dell Wireless WLAN Card Utility. I have a Dell Wireless 1510 Wireless-N WLAN Mini-Card.  
Cannot Add network using Dell Wireless WLAN Card Utility