We’ve seen this once before when a user renamed the installer to start with the word “factorysql”. The installer actually just checks to see if there’s a process running that starts with “factorysql”, and if the installer is named something like that, it will be found.
So, if your installer fits this case, just rename it to something else (like “iainstaller.exe” or something).
If that’s not the case… open the task manager (which you can get to by pressing CTRL-ALT-DELETE, or by right-clicking certain areas of the task bar). Click the “processes” tab. At the bottom right, make sure the “show processes from all users” is selected. Sort by name. Is there anything running that starts with “FactorySQL”? If so, you can end it. Since you uninstalled, there obviously shouldn’t be anything, but this is the only way it checks to see if something is running.