Hack to In-Place “Downgrade” from Windows 7 Ultimate or Professional to Less Premium Editions

stumbled across this “duh” of a hack to allow up/downgrading (depending on your perspective) of a more premium version of windows 7 to a less premium version.  why would you do this?

if you were running a beta or rc version of windows 7 you can “upgrade” to a retail edition without wiping the system.

meaning those win 7 home upgrade dvds i pre-ordered for $50 when i decided to go legit with windows 7 in the summer won’t a) go to waste or b) require me to wipe both systems, install XP or Vista, then upgrade to windows 7.

Hack to In-Place “Downgrade” from Windows 7 Ultimate or Professional to Less Premium Editions » My Digital Life.

this is especially handy considering i’ve effectively failed (several times) to upgrade from a fresh windows xp install to windows 7.  (could that have something to do with the fact that the xp install was cracked or not activated before the upgrade?  it’s possible.  why did i do an xp-to-win7 install instead of a vista-to-win7 install?  i figured xp would be a faster install process.  which it would have been…if it worked.)

the “duh” part of this hack is that basically you’re finding a registry value that says “this os is Ultimate edition” and dumbing it down to say “this os is HomeBasic edition” or whatever.  given that the alternative i was beginning to consider was to find a crack to extend the lifecycle of the evaluation version indefinitely and use the retail versions if i actually did for real need to wipe the systems at some point in the future, i think that — despite this not being microsoft’s favorite idea in the world — it’s at least better than other options.