Do
NOT install the game from the CDs. Unlike the copy of Guild Wars you have installed, the CDs are static - which means if you install the game from them you'll have to download
ALL the updates that were made from the time the CDs were released.
Whether you've bought Factions or Prophecies, your best option is to download the client from the main GW site (
http://www.guildwars.com/) as that is always the most current version of the game.
Example 1: I bought a Factions code online, through the NCSoft store. Without downloading anything, I loaded up GW and added the code to my existing Prophecies account. Immediately, I had access to creating a Factions character.
Example 2: I wanted to show Prophecies to a friend with a slow connection, so he insisted I bring the CDs instead of downloading the client from the site. He ended up having to load at least 2000 files while trying to enter any new area, which was murder on his slow connection. As a result, he wasn't exactly as excited as I hoped.
Save yourself the trouble and use the client from the main GW site,
always.
Oh, and happy birthday!