You need Administrator rights to do this -- if it is your own PC, you probably have Admin rights.
I like using Control Panel, which you can run by typing "Control Panel" into the Search Bar. When it opens, choose "Programs and Features". Look for "NI Software", and select it. This starts NI Package Manager, which is the Installer/Uninstaller. Uncheck the box "Products only". Check the box on the far left that says "Name" to select everything listed. Click "Remove" to start the first step in Uninstalling, which can take tens of minutes.
Reboot when asked. Now do the same thing again. When you open Programs and Features in Control Panel this time, you should only see NI Package Manager (which you did not check in the first step). [In my experience doing this a dozen or three times, "NI Software" was not present at this step. If it were, I'd click it and see if NI Package Manager shows other things (other than itself) to uninstall, and if so, I'd uninstall them]. You should see only NI Package Manager. Select it to uninstall. You will get a warning, but if this is the only thing showing in NIPM, then select it.
After the reboot, run the same steps "one more time". You may see some NI Software "magically reappear". I think these are older "pre-NIPM" products supporting versions of LabVIEW earlier than the release of NIPM. If a list of products appears, select them all, reboot, and you should be done.
My recommendation, at this point, is to stop. Certainly do not attempt to do any "registry cleaning". You might be able to remove "National Instrument" folders in "Program Files", "Program Files (x86)", and "Program Data", but unless you are pressed for disk space, I'd advise leaving them -- if you later install LabVIEW, they'll be over-written.
Bob Schor
P.S. -- if something doesn't seem to work, stop, and make as careful a description of what you did and what happened so we can possibly help you out. If you are nervous, first back up your PC "just in case" (which will almost certainly be necessary if you start mucking with the Registry -- I did this, myself, in 2017, twice ...).
