Can Not Install/Uninstall

I have no idea what happened really but I get errors of different kinds like “failed to premature error” (of course no error number) and other failing errors, rarely any codes, from Office and Norton. I lod anyhting in Office it was to reinstall componets but then fails. Uninstalling/repairing/installing all fail. Norton was doing the same. Says files missing and can not reinstall.
I read some things and tried to reinstall windows Installer but it will not overwrite newer files.
Any ideas please???
So much for enjoying ymself this weekend. I been at ths since last night. It may have happened when uninstalling Family Tree Maker. That was the last thing I did.
Thanks.