Infamous DeepCheck failure when installing dot net 3.5 SP1

I'm preparing my demos for PDC and one of them absolutely requires .net 3.5sp1  [can't tell you which one otherwise I would spoil it :) ].  I was installing all the requirements for my demo VM, you know, windows 2008, SQL, CRM (of course), VS and by the time I reached .net...  beeep an awful message (DepCheck indicates Microsoft .NET Framework 2.0SP1 (x64) (CBS) is not installed) that didn't seem to go away no matter how many times I  uninstalled/reinstalled previous versions of the framework.

 Turns out that W2K8 comes with .net 2 sp1 pre-installed but, for some reason my copy was corrupt so when 3.5 sp1 attempted to silently update it to 2.0sp1  it failed (lost already? yes, a bunch of intricate things going on). The problem is that you can't manually install/uninstall .net 2 sp1.

 So, how did I solve my problem?  Turning-on windows update. One (or many) of the updates applied to my server fixed .net 2.0 sp1 and the installation of 3.5 sp1 succeeded...  fiuf!   After hours and hours of preparing the demo machine seems that I can finally start to work on the fun stuff.

If you are wondering why didn’t I reuse a pre-built VM?... the answer lies in the contents of the demo… pretty new stuff that I had to set manually.  Those attending at PDC will see it firsthand ;)