As mentioned in a couple of my previous posts I have an 18 month old, Dell XPS M1330. The migration from Windows Vista 32bit up to Windows 7 64bit for the most part has been seamless. But for the most part is not perfect and one of the long standing issues has been getting the Bluetooth functionality to work. Unfortunately Dell does not offer official 64bit support for what they now deem a legacy machine and so I had to do some trial and error research.
First off there is a strange Dell bug whereby the Bluetooth function is switched off and is not detectable. This means your Windows 7 will not detect the presence of the Bluetooth hardware, even if the correct drivers have been installed. So if it seems your Bluetooth hardware is invisible yet it shows up in your laptop’s BIOS then you might need to download and apply the Dell BTW Radio ON, A00 patch and fix.
The M1330 usually came with a Dell Wireless 355 Bluetooth Module (Bluetooth 2.0 + EDR) which has not received any driver updates since October of 2007. I suggest you can instead use drivers designed for a more modern piece of hardware such as the Wireless 370. None of the driver documentation points to legacy support but after a month of constant use. I have found no incompatibilities or bugs using 64bit Wireless 370 drivers on the 355 Bluetooth Module.