XP SP3 and MCE
As many know, Windows XP MCE by default does not allow you to join it to a domain. Variations of the infamous "Banana Hack" are available to allow MCE systems to join a domain. I posted about my experience here. What the banana hack does is to change the 'IsLegacyMCE' register key from '0' to '1'.
With XP SP3 set to release in a few days, I tried installing the XP SP3 RC2 to my babana-hacked XP MCE computer. The result was that after installing SP3, my computer went into a constant reboot loop. I was able to boot into Safe Mode, and uninstall SP3, and then the computer booted up normally.
Before uninstalling SP3, I did check the 'IsLegacyMCE' registery setting, and it was still set to '1' - which means that installing SP3 does not overwrite that reg key. However, something else in SP3 is certainly stomping over the ability to let MCE join a domain.
So, at this point, XP SP3 is out for my MCE computers.
-kw