Cannot install CD 2021

I have a perpetual licence for Coreldraw 2021, but a while ago uninstalled. Now when I try to install it won't work, I get a message that the installation has run into an unexpected error, non-specific, but a Corel webpage opens to tell me this. No clue as to why, no error code or anything to go on. 

I recall before trying to install Paintshop Pro X9 sometime ago which didn't work, and when I installed/uninstalled that it appears to have done something to my CD 2021 install, which is why I uninstalled it in the first place. 

All other software, etc., is running fine, on a Windows 11 PC with plenty of RAM, i7 processor, decent graphics card. Perhaps I need to install a missing runtime version (that is me flailing in the dark here!).

Have been using Affinity quite successfully for work, but it would be nice to get CD back as well even though it's non-critical for me these days.

Any solutions/ideas would be much appreciated.