Thunderbird seems to be corrupt. It will not display some images in open emails and last night my theme suddenly stopped working and the only theme available was the default one. When I look at the Add-ons, the only theme shown is the default one and I'm unable to install ANY other theme. I see the screen in the screenshot, but no matter what I do no action at all occurs when I click on any of the buttons/links. It just appears to refresh the same page you see in the screenshot. I have tried uninstalling and reinstalling. I do NOT want to delete my profile because I have years worth of work tied up in my various email accounts and folders. I tried the option to install an add-on (theme) from a file. Didn't work. I tried disabling my AV software. Didn't help. I also tried installing a theme from the Mozilla website using Firefox - clicked on the button that said "download for Thunderbird" or something like that. Nothing happened. My Firefox seems to be working properly in all other ways. I appreciate any help you can provide with the problem of images not displaying and themes not installing.