I looked in a couple other threads, where the same issue was mentioned. One said to delete the latest update file in the updates folder in my WoW install folder in Program Files. I did so, and tried to run the game again. The same issue occurred.
I tried running both the launcher and the game client directly. The wow.exe shortcut in my install folder simply opened the launcher, which had the same issue.
Then I went to "Preferences" and changed the language settings to Spanish, since the other threads say that changing language settings helped. The launcher proceeded to update and then close. When I reopened the launcher and changed the language settings back to English, it gave an error saying that game updates could not be acquired, and the launcher closed.
I also tried moving the WoW install folder to my desktop, another listed solution. No dice. I then moved it back to Program Files.
Figuring that the deleted file might be the problem, I went to my Recycle Bin and restored it, but this did not fix the "updates not found" error.
I tried rebooting. Again, no luck.
Then I tried a reinstall. The reinstall launcher opens, displays a box that says "Updating Files..." and then opens a screen with an "Install button" and plays music. Upon clicking "Install", I get the following error message:
"Failed to download a required installation file (http://dist.blizzard.com.edgesuite.net/wow-pod/InstallData.Master.3a/Win/wow_enus_web_unencrypted_win.blob). Please check your internet connection and try again."
Clicking the "Ok" button on the error dialog closes both the dialog box and the installer.
My connection is fine. Trying to visit the dist.blizzard.com link redirects to a Google search. I'm not sure what else to do to try fixing the issue.
EDIT: WoW was working fine for me last night about 2200 hours EST (10pm, 7pm PST).
As far as OS goes, I'm running Windows 7 32-bit.