Close Riot Vanguard and any Riot games
Open Settings
Go to Apps
Open Installed apps or Apps & features
Find Riot Vanguard
Select Uninstall
Confirm the uninstall
Restart your PC
If Vanguard remains, open Command Prompt as administrator
Run `sc stop vgc`
Run `sc delete vgc`
Run `sc stop vgk`
Run `sc delete vgk`
Delete `C:Program FilesRiot Vanguard` if it still exists
Restart your PC again