ITunes 5 Won't Install -- Hangs on Unscheduling Apple Software Update

Question

Windows 7 64bit
Trying to update from last version to new version.  Install goes until it hits the part where the dialog box says "Unscheduling Apple Software Update," the green bars goes a partial way, stops, retreats.  Another dialog box appears and says "There is a problem with this Windows Installation Package.  A program required for this installation could not be run.  Contact..."
Then it backs out and reverts to the original/last iTunes version.
Any suggestions?
Thanx!

Answer 1

Here's the deal - 
1.  can you install itunes via the APPLE SOFTWARE updater?
  I couldn't  so I downloaded ITUNES and tried to install it that way.   Hence  I got the same error hang as you.  Nothing worked,  (Multiple attempts at uninstall reinstall,  stopping of Services,  Reg cleaners  etc..)
2.  If answer is NO to #1 you must fixe the APPLE SOFTWARE UPDATE Program. 
OK  so I couldn't find a Download for this.   But:  if you have WINRAR,  open the ITUNES.EXE and extract the APPLESOFTWAREUPDATE.MSI file.  Execute the APPLESOFTWAREUPDATE.MSI separately.   And you will not be able to install it and have a similar issue as per your Itunes install.   This of course leads you to believe that the Itunes.exe  install is also installing all of these components including the applesoftwareupdate silently.   It must BOMB at that portion of the install and you are done.  
3.  Your goal now is to get the applesoftwareupdate installed.   How do you do this.  Well -  here is what I did.
  a.  downloaded and RUN a PC  Installer FIX it tool from Microsoft.  This is a replacement for the older MSI fixer they used to use.
  http://support.microsoft.com/mats/Program_Install_and_Uninstall
b. It will list programs to attempt to fix.
  choose  AppleSoftwareUpdate.msi
c. Once it is done,  then reinstall apple program updater using
AppleSoftwareUpdate.msi
Finally it should install since the Microsoft tool appraently fixed corrupted installation files in your registry for this application.
(Please note:  that I also disabled any apple related services such as BONJOUR or IPOD DEvice RUN:  services.msc to get there -  although this man not be necesarry.)
Hence Launch this APPLE UPDATE SOFTWARE (Click the ICON in your Start menu)  it should list ITUNES
select ITUNES from here and it will update.
KEY HERE is to ONLY UPDATE APPLE Stuff via the APPLE SOFTWARE UPDATE program.  If that program is not working fix it.  Then Bingo.
I am sorry to see folks having this problem for weeks.  
APPLE,   Spread the word.  PC's can get corruption in the registry on your product should the update be stopped or computer shut off during an update.  etc...   Please improve your software updater program to check for invalid registry upon launching the app.  This will prevent people thinking it is an APPLE issue.  It appears to be a problem on your PC's registry settings for the APPLE Software update.
Bruno Ricci