Hello and thank you for your question. I look forward to assisting you today. Can you tell me a little more about the problem please? Have you been using Thunderbird and lost your password, or are you trying to set it up, etc.
My apologies the delay. What version of Windows are you running?
The first thing I would like to have you check is your Java updates to make sure it is current. Not having a current Java update can cause problems like you describe.
Go to this LINK and click on the Download and Install link on the page. Follow the instructions for the installation process. Once it is complete, restart your computer then try your Thunderbird again to see if there is any change. Let me know what happens please.