Hello, I'm using version 3.6.13 I'm on a Windows 7 platform In Thunderbird or any other software that provides a hyperlink, clicking on the link will not activate Firefox if it's not running, or it won't open a new window if it is running. I have disabled all addons, restarted, and it still doesn't work. I have not installed any new devices, such as printers, for at least a year or more. I use Avast for protection since I bought this PC I do have Spybot resident. I would provide a list of all my installed software, but I don't know how to get the list. Thank you, Robert