Changing keys

I used Raiins key changer, seems my main key got banned some how so ima buy a new key for 20$. But first, I deleted the ArmA 2 OA folder within the regedit. and started up ArmA OA through steam, but its not readding another folder with my original key? And another question, once i get my new Key how could I change it? I know there is posts, but its kind of confusing. xd any help would be thankful.

--Nevermind. I got it d:

why buy new key for 20$ if you can get one for cheaper?

Because I don't want to take a chance of someone using the key if i get sold one like one of my friend's.