Ensure that the game and the Riot Vanguard software, which is used for cheat protection, are not running. If they are, you can close them from your system tray or use the Task Manager (press CTRL + SHIFT + ESC and find them in the list of processes).
Press Windows key + R to open the Run dialog box. Type control and press Enter. This will open the Control Panel.
In the Control Panel, click on Programs and Features.
Scroll through the list of installed programs until you find Valorant.
Click on Valorant to highlight it, then click Uninstall. Follow the prompts to complete the uninstallation process.
Repeat steps 4 and 5, but this time find and uninstall Riot Vanguard.
After you have uninstalled both Valorant and Riot Vanguard, restart your computer to finish the uninstallation process.