When I started the Launcher, it was left on Minecraft Dungeons but the Launch button had the 'Repair' text shown; As soon as I clicked it, the Launcher closed. I tried to open it again, via shortcut, but this time it became dead and asked if I wished to delete it.

I looked into the Installer's file directory and the exes have been removed. So I downloaded the latest installer, from the minecraft.net website, and it runs fine, the first time and the newly installed launcher runs too... only once again, I am back at square one. Subsequent attempts at running the Launcher's Installer only stopped, showing a message that I have to verify that I have access to the directory.

I am not sure if this is caused by a virus or something else. I tried everything including setting permissions in the Installer's Properties window.