Thunderbird unreadable emails

I uninstalled an older version of Thunderbird and installed the latest. That was a big mistake. Now all email comes in in what I would describe, as "source code". The right scroll bar is missing so I can't scroll down and the pages start with items like x-Account key; X-UIDL; X-MOzilla status, etc. etc. I uninstalled Thunderbird and went back to the older version but it is also affected. I ran malwarebytes to check for a problem but that shows no infections. How do I get a usable Thunderbird back or is there a similar email program that I can use?

 

Try going to View>Headers and select Normal.

 

Thanks so much not only for the correction to Thunderbird but also for the install recommendations.