Firefox 39.0.3

Sometime last night, Firefox updated yet again, to 39.0.3 and since then, my Norton Toolbar, and access to my Password Vault is gone; if I open the Add-On page in Firefox, the Norton Toolbar isn't even listed...i.e., it isn't disabled, it's *missing*. Only suggestions I've found have been assuming that the Toolbar is there and all I need do is enable it. I've upgraded to Windows 10, and Firefox (and the Toolbar) were working perfectly until this last Firefox update.