Whatever is launching may not be "named" Driver Booster per se.
Take another look at the current startup apps and applications - if you find something that you do not or cannot identify then that will need to be separately researched.
Another place to look is in Task Scheduler.
What browser(s) are you using?
What URL (if any) is shown with respect to the source of the setup download?
For example- here is where I found Driver Booster:
https://www.iobit.com/product-manuals/db-help/
The link includes how to uninstall driver booster. Try the Windows 10 uninstall.
If that uninstall fails then you may need to install Driver Booster again in order to be able to get a complete uninstall.
Just ensure that you are at the legitimate website for Driver Booster.