Do you still have the old computer up and running, and the bookmarks were cleared? Or you don't have the old computer up and running, but the new computer did not receive its bookmarks?

If you still have the old computer up and running, try using the Restore feature to load a backup of your bookmarks. This article has the steps: Restore bookmarks from backup or move them to another computer.

If you don't have the old computer up and running, hmm, how many email addresses do you use?

Please note that you cannot Reset your Mozilla/Firefox Account password because that will flush your Sync data. (The exception is if you have a recovery key, I think.)

You can install the About Sync extension to check what data is stored on the Sync server via the about:sync page provided by this extension.

• About Sync https://addons.mozilla.org/firefox/addon/about-sync/

Close and restart Firefox to access the about:sync page added by this extension (see the about:about page for possible about pages).