I am running Thunderbird on Windows 10 Pro, all up to date and have no issues, so I'd say "yes" to your question about compatibility.

I don't know enough about Windows to make sense of this warning, but I really don't think it's from Thunderbird.

Was this a clean install? If you have an earlier installation, maybe uninstalling the Thunderbird program completely and starting from scratch would be effective.

Your profile containing your settings and your old email messages is stored separately and so should not be affected by uninstalling the program itself.

I have it installed now - took a system restore - said nothing changed but it did allow me to put on the 3 programs I wanted.

the computer was turned on a total of 2 days before this happened just to do updates - then yesterday Microsoft decided we needed latest version of windows 10 and both my computer I use won't handle it - too old - this was the new replacement and has it on it already

I was able to move the profile (had done that before) - finding it now uses up too much memory- sounds like I need to clean up the old emails soon