It was shorter than 1 / 2 hour.
I:
- boot with xp cd
- Pressed enter "to setup Windows XP"
- I pressed F8 to agree to the terms
- I pressed R under the windows partition (the only one)
- Setup showed the progress bar
- It rebooted and I didn't touch a thing
- It went to the boot list, went to the windows xp loading screen, then went to the blue screen of death (and now I'm obviously back at square 1)