I have had the Thunderbird programme on my Windows PC for several years. I have a shortcut on my task bar and check my emails several times a day. I have three separate email accounts on there, all with folders and subfolders, address books etc. Nobody else but me has access to this computer. It's in a locked room in my house and I have the only key. About a month ago I clicked on the shortcut and instead of Thunderbird opening as usual, I got a screen asking me to "set up my Thunderbird". I was completely puzzled. Turned out my Thunderbird program had completely disappeared! I had to re-install it, and because I have three email addresses, I had to waste a lot of time setting everything up again. Very annoying! Two weeks later, the same thing happened. Again loads of office time wasted setting it up a third time. Got up this morning, and yes, Thunderbird has disappeared yet again. When I check the C Drive, the program is not even installed on my PC. How can this possibly be? I'm not prepared to reinstall and then set up my three email addresses every two weeks. Why is this happening and how can I stop it?