My old computer died, so this is a brand new thunderbird install on a brand new computer. When I click a hyperlink url in an email (or the default welcom window), nothing happens. I checked that the default web browser was Firefox in windows, but I also changed it to Chrome to give it a kick. I also went into the advanced preferences to make sure network.protocol-handler.warn-external.http and network.protocol-handler.warn-external.https were set to true (but also checked with false). After each change, I closed TB and relaunched. Under "Settings", in "Content Type", for http and https, I tried both "Always ask" and "use Firefox (default)". I restarted TB after each change. I have searched this forum and for some reason, I just cannot find a solution. I would screen capture an error or whatever, but literally nothing happens when I click on any hyperlink. Any help would be appreciated.