broken hal.dll with XPSP3 - will not boot

After spending about 7 hours getting my work machine to boot, I thought I'd make a few notes, in case it help anyone else.

Background:
- Installed SP3 on Tuesday - no problems.
- An auto update installed last night (Thursday)
- This morning, wouldn't boot:

Windows could not start because the following file is missing or corrupt:
\system32\hal.dll.
Please re-install a copy of the above file.

Managed to get everything back by following the excellent instructions at:
http://forums.legitreviews.com/about6705.html

Really needed the restore disk and the dell resource CD. (Note to self, must check where the one for my laptop is.)

Ended up with a machine which has everything SP3, apart from hal.dll, which is SP2 version. But, everything seems to be ok.

Also had to reinstall IE7 as was on originally, but reinstall of OS rolled back to IE6. This was clever as SP3 is supposed to stop moving back to IE6.

This in turn has fixed a broken IE7, which couldn't save settings, after upgrading to IE8 beta and then downgrading.

Had issues reconnecting to domain, but solved these by disconnecting from and reconnecting to the domain.

Leaving my machine dual boot though. just in case.