If you're getting that far, it's not the boot that's broken, it's deeper in the OS and the repair disk won't help.
If this happened as a result of a WUD you can get free one-to-one assistance from Microsoft.
Follow the links from the WUD "update history" page and you'll find a MS email address to write to.
Try booting with any "live" cd that will allow you to view the filesystem, if the system drive contains both "Program Files" and "Program Files (x86)" then you need the 64 bit recovery disc. If it only contains "Program Files" you need the 32 bit recovery disc.
I hope this helps you out.