You could buy a boxed copy in a local store that sells PC software, often for less than the $50 US retail price.
You then use the 25 character PIN found on an orange label stuck to a card inside the box to activate the trial you already have installed. No need to use the CD at all since you've already got the program itself installed.
I'm going to move your post to the Install/Activate forum since you shouldn't have posted in the Off Topic forum.
OneCareBear