This is barely relevant to anything, I just want to get this information out on the net.
If you are having problems installing a fresh copy of Windows XP on an IBM Thinkpad T20 because the windows installer / setup program crashes repeatedly in random places, this is the fix:
Remove the battery.
I don't know why it works, but I'm guessing something to do with either power management drivers or CPU speed-stepping. I spent probably 6 hours thrashing on this stupid thing before locating an obscure post on an MIT newsgroup. Hopefully this blog will be slightly easier to find if anyone else is ever doing this.