First, you should have received an activation email at the address linked to your forum/game account. Check for it, and also look in your Junk/Spam folder. Be aware that there are some ISPs which have been known to block emails from Frogster.
If you didn't get the activation email, log into your forum account via the Account Management link on the main page. You'll need the email address as stated above and your forum password. Click on the Game Accounts tab and see if, under the "Runes of Magic" header, the game account is "Created". If so, you should be good to go.
Second, start the game launcher and look in the lower right corner for the Region/Language button there. Click it, select USA and English from the drop downs, then click Apply. Start the game.
Hope this helps.
