It seems that all bets are off as far as the June CTP goes.  Get the current product and do a fresh install.  My experience has been that a new OS install is in order, too.  I understand that MS has released, as of last Tuesday or so, yet another new cleanup tool that cleans up after all versions of the CTPs.  It hasn't been tried here, and by now we're smart enough to have Ghosted versions of clean and patched OS installations.

It just does not make sense to try to support an old Beta.