Error code 0xc0000409 in windows XP repair: Setup keeps restarting!

Found this, and it worked.

Ok. Fixed it. I don't know if renaming SPIOSYS.SYS had anything to do with it.

The details were this: Error message popped up during xp pro reinstall. 9 minutes remaining while registering components.

Setup.Exe - Application Error
The exception unknown exception (0xc0000409) occurred in the application at location (0x6976db5f)
Ok Cancel

This might sound simple fix, but getting to the answer was a lot of work, and the lack of any so called MS 'MVP' help/interest in the problem confirms this. Very disappointing. The MVP badge has no worth these days. Especially a non - MVP person can often do a better job!

Anyway, enough ranting, the Fix was to boot from another working partition.
Luckily I had a Winternals 2005 ERD disk in my toolkit from ages ago. You 'may' get by using bartpe or locating a copy of Hirens boot cd.
Or getting this http://icompute.info/repair_windowssystem32config.htm

Once booted I used System Restore from the preinstalled environment to go back a few weeks.
This will prevent the stupid setup from launching.
Now you should be able to boot. Get in fix the problem by running sfc /scannow.

Hope this helps somebody.