Once they get your credit card details they make it very hard to stop them stealing your money each year! The easiest way to stop them is to cancel your credit card!
Add to this that their programs are taking 50% of processor power!
Do not trust this vender. I purchased 3 copies of their antivirus software for one year only, and checked the box for non-automatic renewal. Despite this, when the year was about to expire, they sent me an email informing me they would be automatically renewing my license and charging my credit card. I emailed them immediately to inform/remind them that I didn't want automatic renewal. They sent a confirmation email saying they had cancelled the automatic renewal. Guess what? Despite all of this, they went ahead and charged my credit card! I now have the hassle of getting my money back.