After reinstalling Windows 7, my Bluetooth dongle (a Kensington Model 33348 Bluetooth USB Adapter 2.0) wouldn’t talk to my Microsoft Bluetooth Notebook Mouse 5000. I would try to Add the mouse device but Windows did not see it. I browsed around quite a bit. Here is how I finally fixed the problem: (via)
Enjoys Windows 7 uForums
Re: MS Bluetooth Notebook Mouse 5000 not working
Went to another site and found a solution that worked. You might want to try it out.
Go to START icon and type in services.msc and select services.
The dialog box that opens has a long list of stuff but look for BLUETOOTH SUPPORT SERVICE. Double click to open. Make sure it is AUTOMATIC. Go to the LOG tab. Choose THIS ACCOUNT and type in LOCAL SERVICE. A list of password (a 15-dot string) would appear. Delete all the password in the PASSWORD and under CONFIRM. Choose Okay.
It will ask you to restart the service. Once restarted, turn on your bluetooth adaptor again. Put your mouse in pairing mode and add the mouse. It works perfectly!!!
Give it a try and see if it helps.