re :So I think that if you have the same E-mails with the same password, on two computers, on one you will not be able to send any E-mails from the second one.

You should be able to send on both.

On second computer: when you try to send what happens? what error message do you get....word for word?

Please post information. In Thunderbird Hep > Troubleshooting Information click on 'Copy text to clipboard' button In this forum question, right click in a 'Post a Reply' text box and select 'Paste'. Edit/Remove all info on fonts and printers but nothing else.

I phoned the help line but he said he did not know the answer and hung up. I looked at the forum but could only find stuff about moving everything to a new computer and about working and storing off line. My question is: "If I download TBird to me new desktop will it simply copy (NOT move) from the app which I will be leaving on the laptop (Including existing e mails and mail addresses?

There is no phone help desk so beware who you call. Please start your own thread with your questions.