Issue:
Please install windows vista service pack 2 before proceeding.

Fix:
1. Browse to the DVD in Windows Explorer
2. Right click ffxivsetup.exe and click Properties
3. On the Compatibility tab, uncheck "Run this program in compatibility mode for:" (if you can't uncheck it, you probably need to click "Change settings for all users" at the bottom of the same dialog)
4. Reinstall normally
from ffxivorigin