Let me start by stating that the subject line might be a bit deceptive
in conveying the complexity of this problem. 

The problem:
My sister had a previous version of iTunes on her computer and her 
boyfriend tried to update her to the lastest version (Version 6.x).
However, something happened and now neither iTunes or the required
QuickTime update will install (and she lost her previous iTunes and 
QuickTime installation).

Without fail towards the end of the installation an InstallShield or
Windows Installer error code is thrown. 
We spent a day researching this online and tried several 
things (from fake QuickTime codecs to messing with registry keys) and 
nothing worked.

Her computer is about 2 years old. It has Windows XP with Service Pack 2.
Once I have access to her computer tonight I will post the exact error 
code. Googling this problems shows there are enough people with this problem
to proove that this isnt some obscure problem so I know it should be
answerable.

Our last resort will be to reformat her computer but thats insane.
We'd like to resolve this quickly.
There will be a decent tip for the researcher that solves this problem.

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Clarification of Question by asdf123-ga on 10 Apr 2006 07:33 PDT

Yea, a system restore is the first thing we tried. 
We even went back a month just to be sure and it didnt work at all.
iTunes install still always throws the same Install Shield error code:
http://consumer.installshield.com/common.asp?source=all
Unfortunately I forgot which one exactly at the moment.
Eventually after hours of fiddling Quicktime install started throwing
an "error code -3" also.
I tried Apples site and did most of their suggestions but that 
didnt help.
http://docs.info.apple.com/article.html?artnum=93976
Chaos. Total chaos, lol.

---

Clarification of Question by asdf123-ga on 10 Apr 2006 18:34 PDT

Ok. I now have access to her computer. 
The iTunes installation error code is "1628: Failed to Complete Installation".

Such as here:
http://consumer.installshield.com/kb.asp?id=Q108464
http://www.smartcomputing.com/techsupport/detail.aspx?guid=&ErrorID=27321

As for the comment to uninstall, lol, that was obviously done.
Im very competent with computers and have tried all of installshields
suggestions but that error remains.

There is a $10 tip to the Researcher who solves this.
This cant be that hard. We must just be missing something.

---

Clarification of Question by asdf123-ga on 11 Apr 2006 15:20 PDT

Seeing as how it seems only 5 of the last 60+ questions
were answered is it safe to say this will never get answered?

---

Request for Question Clarification by legolas-ga on 12 Apr 2006 21:29 PDT

Have you tried the steps outlined here:
http://consumer.installshield.com/kb.asp?id=Q108334

and here:

http://docs.info.apple.com/article.html?artnum=93976

Please follow the instructions to the letter and let me know if it
solves the problem. It is very important that you read CAREFULLY and
follow the directions contained.. Specifically, you may want to try
this:

Clean up iTunes installer files on the computer

You can download the Windows Installer Cleanup Utility from Microsoft,
which will clean up any leftover installer files that may be causing
issues with your current installation. To do this:

   1. Click here ( http://support.microsoft.com/default.aspx?scid=kb;en-us;290301
) first, and read the important information about the software.
   2. Click the "Download the Windows Installer Cleanup Utility
package now" link on that page to download a file titled msicuu2.exe.
   3. Open the msicuu2.exe file and follow the prompts to install it.
   4. On the Start menu, point to All Programs and then click Windows
Install Cleanup; the Windows Installer Clean Up Utility window
appears, listing software that is currently installed on your
computer.
   5. Select iTunes from the list and click Remove.
   6. Click OK in the confirmation dialog that appears.
   7. Repeat steps 5 and 6 if you have multiple iTunes entries listed.
   8. Select QuickTime from the list and click Remove.
   9. Click OK in the confirmation dialog that appears.
  10. Repeat steps 8 and 9 if you have multiple QuickTime entries listed.
  11. Click Exit.
  12. Restart the computer.
  13. Try installing iTunes, iPod, or QuickTime software again.

Legolas-ga

Did you try going to a previous restore point?  If you click on start,
select programs, accessories and then System Tools, you'll find a
program called "System Restore."  Using it will let you roll back your
systems configuration to the point before the upgrade was attempted.

Give that a try and see what happens.

Have you tried completely uninstalling both iTunes and Quicktime, then
reinstalling the latest version?

Go to Start > Control Panel > Add / Remove Programs.  Scroll down the
list until you find iTunes, highlight it then click the button Add/
Remove.  Then do the same for Quicktime.

Once removed go the the respective websites to download the latest versions

Uninstall both quicktime and iTunes. Using a program like winRAR unzip
the zip pacckage then run the installed seperately

I had problems with quicktime/itunes, and what I had to do was
uninstall both, delete it's folders on the disk, and then fire up
regedit and methodically search for itunes and quicktime keys in
registry and delete them.  You'll want to create a system restore
point, and really should do a full backup before you begin this of
course, since as always any time you are messing around with the
registry you can potentially cause some serious problems with your
windows installation.  Once I had all traces removed from my computer,
I was able to reboot and install the latest version just fine.  I
think the reason why is I had quicktime installed from before it was
integrated into itunes, and that may have been causing a conflict.

I had an issue such as yours.  I cannot recall the error, but it sure
seemed like some left over installer garbage was geting in the way.  I
had removed every registry entry I could relate to
iTunes/iPod/Quicktime. Nothing worked. The error persisted.  I gave up
and decided it wasn't going to work without reloading the OS or
possible spending hours on this single issue.

Then I ran across the quicktime stand-alone player.  I was able to
install the quicktime player without iTunes.  This allowed me to to
view the quicktime file I needed to see.  I then uninstalled this
stand-alone player using add/remove.  I could now install the latest
version of iTunes without issue. iTunes/iPod/Quicktime all worked!  I
can't say why it worked, but I'd suspect installing the stand alone
player overwrote some bad files or registry entries, allowing a more
clean uninstall (in my opinion few uninstallers are perfect).

Perhaps you have a similiar issue...

http://www.apple.com/quicktime/download/standalone.html

First thing's first. Use the Uninstall Programs feature. If this is
still crashing, delete the iTunes directory in the Program Files.

After doing that, delete the registry settings iTunes has set. Reboot,
and install the newest version from scratch.

Hope this helps in some way.