Which folders are you referring to?
The safest thing to do is to rename the folders and then reboot to see if the system works OK.
If it does, then leave the folders alone for a week (just in case) - and see if there are any problems for a week.
If not, it's probably safe to delete them then.
Inside both folders there was this file:
These files were found inside windows\installer:
(both say "this installer database contains the logic and data required to install(...)")
I moved everything to another folder and I ran one of these two shown above.
I was able to reinstall the app. After uninstalling the app, Iobit performed a 'deep clean' and removed the entries in the registry.
Then I ran ccleaner so it could delete the remaining stuff and the only thing left in the win\installer folder was one of the two files (I can't remember which one)
and a folder in program files with these two files:
I've also moved this folder to another location in case things go wrong.