I'm sure I'm not the only one who wanted to make the Dell Wireless 410 minicard hardware work in Windows 7, so I'm posting this to share what I already figured out on the subject.
Dell's support site lists drivers for the Wireless 410 minicard for Vista, XP, and other operating systems / operating system versions but the driver is curiously missing from the list of drivers that are intended for Windows 7 (32bit or 64bit). Vista was the original OS on my m6400 precision mobile workstation, but as everyone knows by now, Vista sucks, and Windows 7 is tolerable. So, as of July, 2011, Dell provides Windows 7 drivers for just about all of the other hardware, but the "Dell Wireless 410 Bluetooth" device driver is still missing.
The 410 minicard apparently combines Bluetooth and WUSB "Wireless USB" (i.e. UWB "Ultra Wide Band") devices on the same card. Under Windows 7, it seems only one of those devices can be enabled at a time. The UWB/WUSB "side" of the card can be enabled by installing the Vista (64bit or 32bit depending on OS version) driver using Windows 7's "compatibility mode" to run the installer (setup.exe) but having that driver installed prevents Bluetooth devices from connecting, even if a Bluetooth driver is installed. The Bluetooth "side" can be enabled by installing the Windows 7 "Wireless 370 Bluetooth Minicard" driver, but that leaves the UWB/WUSB "side" of the device showing as "Unknown Device" (VID_413C&PID_8149) in device manager.
In my case, I needed the Bluetooth device, but have no real use for the WUSB/UWB device, so I just installed the "Wireless 370 Bluetooth Minicard" driver, and I'll have to ignore the "Unknown Device" in device manager. Incidentally, when the "370" driver is installed, the hardware is still recognized and listed in device manager under "Bluetooth Radios" as "Dell Wireless 410 Bluetooth Device" (VID_413C&PID_8152 / last 2 digits different from the UWB device).
Also, after finally getting a driver installer to detect the correct device and make it show up in Device Manager, the power management defaults to an annoying setting which may cause the Bluetooth radio to intermittently switch off. Right click "Dell Wireless 410 Bluetooth Device" (under Bluetooth Radios in device manager), select "properties", switch to the "Power Management" tab, and UN-check the option labeled "Allow the computer to turn off this device to save power"