Hi,
I understand you have issues pairing devices via Bluetooth. I will be glad to help you. I understand the frustration when things don't work the way it should.
What is the make and model of the Bluetooth device?
Method 1:
I would also suggest you to run the Hardware and devices troubleshooter to troubleshoot the device:
Please follow the below link to know how to run the troubleshooter.
http://windows.microsoft.com/en-us/windows7/Open-the-Hardware-and-Devices-troubleshooter
Method 2:
If the issue persists I suggest you to install the important and optional Updates on both the computers
You can follow the below link to know how to install
http://windows.microsoft.com/en-US/windows-vista/Install-Windows-updates
Hope this information is helpful. Please post with the results. I will be glad to help you further.