Motorola Milestone Android - Bluetooth Issue - Paired but not connected
On a PC, it's often a driver issue. I followed these steps with mine last night:

Before doing this, disable any processes using bluetooth devices


Download the 'Windows Mobile Device Center' ( current version is 6.1 ) which you can download it from here
this works for both Vista and Windows 7. I've tried it on both.
Install the downloaded software but it may not look like it worked on Windows 7 PCs. Vista automatically configures the settings on the bluetooth devices but for those who have Windows 7, here are the things you should do:
Go to 'Device Manager' from 'Control Panel' -Or- just right-click on Computer Icon and choose 'Properties' and then click on 'Device Manager'.- You'll see 'Bluetooth Peripheral Device' under 'Other devices'





Right-Click it and click on "Update Driver Software" -Or- anyway you find it easy to bring up the Update driver window.
Click "Browse My Computer for Driver Software" button.
Click "Let Me Pick from a List of Device Drivers on my computer".
Select 'Bluetooth Radio' from the list if it asked you to select and then in the next window, it will show a list of drivers with Company Names in one list and Drivers in another. In the Company List choose 'Microsoft Corporation', not only Microsoft.






(From the drivers list there may be one or more drivers with the name "Windows Mobile-Based Device Support" with different driver versions. Select one or the latest. )
Ignore any warnings and keep pressing next and then Finish at last. If all goes well, the last screen will show the message that device driver is successfully installed. ( Click 'YES' in the box )




Now, after manually updating the driver for your bluetooth device, in 'Device Manager' when you click on 'Bluetooth Radios', it should display one more item which will say 'Windows Mobile-based device support'. 

After you do this, restart all processes using bluetooth devices

i got this process from here, refer to it if you need help.

Good luck!! :)