Accounts being Deleted because they're so Old

3 years ago, I made an account on World of Warcraft. I bought vanilla WoW retail, as well as Burning Crusade at retail (meaning, I bought the physical CDs). I played it for a while, then went on a hiatus.

3 years later, the email address that I used with my old account is long gone. And the computer that I used to play WoW on 3 years ago is pretty much dead (although, I could probably wipe the hard drive and reboot it and hope it works). I decided to play a trial of the game to see how much it's changed. I made a new account with a new email address. Afterwards, I decided to buy the game. I went to enter the authentication key from my retail vanilla WoW from 3 years ago, and it wouldn't work. I noticed that my Night Elf Warrior from 3 years ago, Krugohaul, wasn't in the armory, either (although when I DID search for my old character, the database found it, but it said that the character was not available when I tried to check out my character's armor and weapons and what-not through the armory. It's like my old account disappeared from the face of the earth.

Here's my problem: the authentication key for both of my vanilla WoW and Burning Crusade games were used on my old account, and I cannot retrieve my old account because Blizzard's database says it does not exist. I cannot use my old authentication key on my new account, just because I haven't played on my old account for 3 years?

Does this mean I have to buy new copies of vanilla WoW AND Burning Crusade? Or is it possible I could uninstall WoW from my old computer and hope that authentication key can be used on my new computer? I really hope I do not have to buy the games again, because I will lose a lot of faith in Blizzard if that happens.