Re: Vista won't complete installation

I also was unable to upgrade from Vista Home Premium to Vista Ultimate.
Hung at 74% of "Completing Installation". Finally gave up after an hour
or so (being confused by continued disc access that made me think it
might really be doing something) - and shutdown by holding the power
button. Thankfully when I powered up again it backed out to where I
started. Then it was a search for the log files that would tell me
something. Just searched on *.log in C: setuperr.log in "Pathfinder
(C:\$WINDOWS.~BT\Sources)" looked interesting. at the end of this file
there was an error relating to a service called SYMFW. Googling this to
find out what it was, discovered that it was a Symantec process. Indeed
Norton Internet Security 2009 was installed. I uninstalled NIS and
tried the upgrade to Vista Ultimate again. It worked this time!

Lesson: look at the log files first before trying all of the myriad
suggestions you find on boards like this.:)