Once you have obtained a valid key through an official purchase or giveaway: Open the main window.
If you want the extra features—like the ad-blocker, disk analyzer, and privacy protection—without the risk, consider these legitimate paths: 1. Use the Free Version Permanently
While the lure of a free premium key is strong, the "verified" lists found on forums are almost always expired or dangerous. Stick to the for basic protection, or keep an eye on the official 360 Total Security website for flash sales to upgrade safely.