I had a similar issue on a Mac where I just had to delete an entire library and some other stuff to finally just reinstall it.
What you're wanting to do is a bit extreme, but in theory it work. Some issues would be cleaning the registry of everything Native Instruments could prove to be tedious. And tracking down all the hiding places of Native Instruments software might take some time. On Windows, some vendors like to sneak files into C:\ProgramData as well as the usual Program Files and Program Files x86 folders. You'll also have to check your AppData folder too as to make sure nothing residual is in there.
In theory yes, that should allow you to reinstall. It honestly might just be easier to reinstall Windows than try and tease out every last NI file/registry entry on your computer.