First question is what can you see on webmail, is anything missing? If your email account is IMAP, many or all the old email may be in the online (webmail) account. Easy enough to check - log in online and see what's there. If you have everything online, when you set up the account in Thunderbird it should download whatever is there. If your email is or was POP, those emails would most probably have been downloaded to your computer and deleted from the webmail server. Also if you used Local Folders to store emails - those would not be on the online server. If you use Local Folders you do need to make backups. Next question - is the hard drive from the old computer viable? If you do not have all your email in webmail, you may need to remove it and either attach it as a second drive to access the stored Thunderbird Profile, or get a tech support service to do that. If you can recover the profile folder it can be moved to your new computer. Search the forum articles for 'move thunderbird profile' to find detailed instructions. Do read the article about the profile - where thunderbird keeps all your data including address books and emails. I hope this helps, Agnes