Had a quirky experience with bluetooth just this past week and wanted to share my thoughts. I was running Windows 7 Ultimate in our demo room at work with a Microsoft Bluetooth KB/Mouse setup and it worked perfectly. I refreshed the box with Windows 7 Pro, guess what? Bluetooth did not work too well with Pro on it, the USB dongle was correctly identified and was listed in device manager without any problems but there was no Bluetooth option in control panel and the the only way to get to the bluetooth manager was by command line (bthprops.cpl). Adding a device failed and I tried all the fix's/reg hacks/drivers I could find via the webs. My only recourse was to install Windows 7 Ultimate back on it, works like a charm.
So I guess there is some kind of difference between the way Windows handles BlueTooth between Pro and Ultimate editions or the Microsoft hardware I have is questionable. A quick glance through google didn't help... any idears?