So are you sating you cannot connect wirelessly anymore? The broadcom Management Program is not necessary. But if installed it will handle the wireless network connecting as opposed to Windows doing it.
If your son deleted the program without properly uninstalling it then it might affect your ability to connect wirelessly.
You can get the latest version of the software from the Dell Downloads & Drivers page for the E1505/6400. In the network section you will find both the drivers and the software for all of the network options available on that model Dell.
You can request replacement reinstallation media for US purchased systems here.Dell Drivers & Downloads for all systems.