Don't, unless you've got plenty of time and patience
Third time I've tried to renew a product, third time it's happened. There's a complicated formula to enter your passcode. Their emails on how to do it confuse you even more. A week of my sending emails they never understood: they kept sending me the same thing over and over. When I screamed CANCEL, REFUND for the 10th time they suddenly realized they were sending me codes for the wrong product. Good software, but unless you've got plenty of time and patience, don't even try.