I hope you understand that I am talking about email addresses, not individual emails.

Why doesn't anyone help me?

I would like to be able to advise you to copy the profile from the old computer. That would bring with it all of your stored messages and your working email accounts.

However you have managed to add one account, so you have found the way to add accounts to Thunderbird. As you seem to have worked that out there is no need to go into details on that topic.

So, what's going wrong with the remaining accounts when you do the same thing?

Thank you for responding. Yes, I added my primary email; but I cannot add the other four. Also, I can no longer reply to my primary email on my old computer, only the new one. To me, it's crazy. I really need help. I leave on Sunday and will not be back for a month. I do not want to take both computers with me.

I think the problem is that I cannot get the two computers to recognize each other, the network only show my desktop and old laptop; it does not show the new laptop. My desktop has not been hooked up since my home was stolen in February.

I'm trying to clarify the issue, first. I think you have three computers: a desktop PC, an old laptop and a new laptop. You had Thunderbird with five working email accounts on the old laptop (and on the PC?) and you want it like that on the new laptop. You have managed to re-create one of the accounts on the new laptop. The new laptop will not connect to your home network; the network shows your old laptop and the PC but in fact the PC is not connected to it. Is my understanding correct? If so, there are two issues to tackle. One is getting the five accounts on the new laptop. The easiest way to do that is what Zenos suggested: copy your Thunderbird profile from the old laptop to the new one. Instructions are here: https://support.mozilla.org/en-US/kb/profiles-tb (see 'restoring to a different location'). The profile is a single (large) folder which contains all your account settings and stored messages. You don't need a working network to copy it across, you can do that simply by coping the folder to a memory stick and transferring it. The other issue is getting your network running properly. Your ISP should be able to help with this. My usual procedure is to turn off the router and disconnect it from the power supply, then reconnect it after a minute or so and restart. Try connecting your computers to it by ethernet cable: if those connections work then you know the router is working and the problem is with the wifi. But that kind of network help is beyond my competence and in any case is outside the scope of this forum.

I finally managed to get them all working after several unsuccessful tries. Thank you for your help.