Komunitné fórum Thunderbird

Usually when I open mail, there are boxes next to each email that I can click to delete. They are gone and I have on the left side a vertical list of tabs that begin with Mail, Calendar, and People and others follow. This panel was not there before and I cannot figure out how to remove it--I think this will restore the boxes I use to delete emails.

I had to buy a new computer and reinstall my Thunderbird. I'm running version 158.0.1 (64-bit). When I have an email with a bunch of replies, it always opens each reply in a separate tab. In the past, the solution was tools -- preferences -- general but when I got to tools, there's no preferences option and I have clicked on everything possible there and in settings. I need the email to open as a single tab, closing a bunch of tabs is a real pain. I'd appreciate if anyone has a solution they can share.

I have swapped my Internet provider fro Inmotion to Bluehost. When the DNS was changed I can no longer receive emails. I am using Thunderbird. Where do I go to change this? I have a lot of emails that I need to keep. I have them on my computer but cannot receive any new email.

I was a COX cable Email customer, when they stopped providing Email my account went to YAHOO, but the Email address stayed the same. I have been using TBird for years. My old computer died, the person that set up the new one could not set up Tbird. I am trying but it says my cox.net site could not be found. PLEASE HELP ME! I love Tbird and hate YAHOO!