I got the same problem today. I have a mid 2010 macbook pro 13 inch. I have windows 7 x64 under bootcamp. All of the sudden the bluetooth adapters just disappeared from device manager. Windows 7 seems totally unable to detect the internal bluetooth hardware. I am currently trying to figure out what caused the issue.
Yes, I'm having this problem and its so frustrating. Bluetooth can't find any devices. I've tried everything. All the support recommendations, "fix-it", services settings, bla bla bla, etc. etc. etc. Nothing has worked.
It started after installing a bigger drive (750GB) into my MBP. Restoring windows 7 from my backup did not work because it reset the Windows drive back to its original size - why can't MS get anything right???!!!
So I had to reinstall Windows 7 from scratch. At first it found my bluetooth mouse but could not connect with it properly - i.e. no response to the mouse after adding it to bluetooth devices.
I followed a suggestion to set the bluetooth service to start automatically and from then on, absolutely nothing has worked!!! No matter what I do, uninstall, install all bluetooth services, drivers, etc. etc., as well as trying Broadcom utility. Its so frustrating because it once worked. What is with windows that bluetooth should completely shut down all functionality like this??? (It still works fine booting into OS X.)