"Script:chrome://messenger/content/mailWindow.js:179" and "Script:chrome....js:173" and "Script:resource"//gre/modules/XPCOMUtils.jsm:323"

I have also gotten messages that say the problem signature is AppHangB1, followed by a long list of detailed data.

I am using Windows 7 on a desktop pc. I can download email just fine. But then I can't open or delete a message or do anything else for several minutes. Meanwhile, I see at the top of my screen that Thunderbird is not responding. This happens whether I am connected to the internet or disconnected. I sometimes get a message that a script on this page is busy or not responding. The scrips have been "Script:chrome://messenger/content/mailWindow.js:179" and "Script:chrome....js:173" and "Script:resource"//gre/modules/XPCOMUtils.jsm:323" I have also gotten messages that say the problem signature is AppHangB1, followed by a long list of detailed data.