Free Trial has destroyed my prior installed old version of Acro Reader

There's no trial version of Reader. It's a free application. You probably installed a trial version of Acrobat (not the same as Acrobat Reader!). And if you were able to edit PDF files before then you didn't have Reader then, either, but Acrobat. If you still have the installer for that older version (and hopefully it's still compatible with your OS) then you should still be able to use it, after uninstalling the trial version.

Note, though, that the trial version automatically converts to a paid license when the trial period is over, unless you cancel it in time.

MOVED TO THE ACROBAT READER FORUM

You cannot edit with Acrobat Reader, you need either Acrobat Standard or Acrobat Pro. So I'm going to guess you were not using Adobe Reader.

It's been so long I cannot remember what warnings come up (I do remember there are some warnings) but Acrobat cannot have more than one instillation on a computer at a time, so if you had a previous version of Acrobat, a new install would have caused the previous one to uninstall. If it did, all you have to do is to reinstall the previous version.