You would have to buy the Burning Crusade download or box set, and install it on your PC (which already has classic WoW installed). It will then prompt you to go to your battle.net account page, and add a game. Here you then fill out the activation key that came with TBC, and your account will be upgraded as well.
Yes, it will upgrade the account, no matter what computer it is on, providing you use the same account.
No, you do not lose any characters when you upgrade your account. The only times you lose your characters is if you happen to delete them, or if Blizzard bans your account and deletes them.
It can take several days after you finish processing the upgrade. Give it a few days.
If your WoW account got banned and it is permanent then you will need to buy a completely new account from a retailer like walmart or bestbuy and if you wish to have The Burning Crusade enabled on the account you will have to upgrade it which can be done online now I beleive. But you will need to upgrade the account again. In addition: you also have to purchase a new burning crusade key
Well, it's all about the account. If your account is upgraded with the code for WOTLK, then you NEED to play on a PC with the version having installed WOTLK. Although, you can play a TBC/Vanilla(Classic) account on a WOTLK upgraded version of WoW. Yes sir eee!
If you have all of the previous expansions, you can log into your battle.net account, find your WoW game management and digitally upgrade to Cataclysm. Or you can buy the expansion pack at a store.
If you already have an active Battle.net account with World of Wacraft and The Burning Crusade registered, all you have to do is install Wrath of the Lich King from a CD or Digital Download. You will receive an activation key with your product - when you log in to your Battle.net account, you should see an option to add a game to your account. Use this option to fill in the key and upgrade your existing WoW account to Wrath. If you do not yet have an active account or a WoW account, you will have to buy and install World of Warcraft, make a Battle.net account and also buy and register The Burning Crusade before you can take the steps above.
you need to put the new key in...
No. If you mean by patches, then yes you can. But not if you are talking about expansions. you have to buy it. My friend currently plays wow because I got on my account and downloaded the expansion and stuff to his computer under my account for free. That's one of the tricks I do to get people to play wow :)
Yes it does. I just installed WoW (+ Expansions) via the wotlk downloader.
because its upgrading your bc or obc or tbc.(if you have it)
You can use the scroll of resurrection from the account management page. If it has been over a year, then you might need to upgrade your login account to a battle.net account. Battle.net accounts are now required of all WoW accounts.