I can't open, reinstall or uninstall my itunes

Question

I downloaded iTunes for the 64 bit model a month ago, and it was working fine. But last week, I couldn't open it anymore.
I've tried to reinstall and uninstall it but a page always pops up that says "The feature you are trying to use is on a network resource that is unavailable. Click OK to try again, or enter an alternate path to a folder containing the installation package 'iTunes64.msi' in the box below."
And I click okay to the use source, but it says "The path cannot be found. Verify that you have access to this location and try again, or try to find the installation package 'iTunes64.msi' in a folder from which you can install the product iTunes."
I have the file, but it's not the "complete" version of it and I can't get the complete version of it... What should I do? Any helpful comments or suggestions are appreciated

Answer 1

When attempting to upgrade the latest Apple Quicktime/iTunes on
Windows7 x64, I experienced the same issues that other people were having: several errors, the upgrade failed, and the existing installation is broken. The issue appears to be the permissions on the keys by the previous version were incorrectly set and are now not accessible. By restoring the permissions on the keys, you'll be able to uninstall the old version and install the new version.
Here's how:
Open the Control Panel and go to Programs and Features. It could take a few minutes for the list to complete populating. When the list is complete, uninstall everything Apple, including iTunes, Bonjour, and Quicktime.
Some will uninstall ok, but some of the components will error out with a message saying that it
"Could not open the key:
UNKNOWN\Components\DA42BC89BF25F5BD0AF18C3B9B1A1EE8\(SubKey Name). Verify that you have sufficient access to that key, or contact your support personnel."
Right click Start and open Windows Explorer.
Make sure that you can see all files. On the Menu Bar, select
Tools, then Folder Options. Go to the View tab. Under Hidden Files and Folders, make sure that "Show hidden files, folders, or drives" is selected. Also, UNselect "Hide protected operating system files". Click OK. You'll get a warning about displaying the protected files. Select "Yes" and OK on the Folder Options.
Navigate to C:\Windows\System32
Find Regedt32, right click, and open as an administrator.
In the left pane, go to the top of the registry, and highlight
Computer.
Search for the offending key. Go Edit, then Find, put in the key name: "DA42BC89BF25F5BD0AF18C3B9B1A1EE8".
Several of the subkeys under this key have no permissions set for them. When you click on them, you will get an error saying "Error Opening Key", "(the key name) cannot be opened."..."Details: Access is denied." Click OK.
In the left pane, right click on the parent key,
"DA42BC89BF25F5BD0AF18C3B9B1A1EE8" and select Permissions.
Click Advanced.
Go to the Owner tab.
Click on Administrators, check the "Replace owner on subcontainers and objects" box, and click on Apply.
Go back to the Permissions tab. Check the "Replace all child object permissions with inheritable permissions from this objects" box, and click on Apply.
You'll get a Windows Security warning about replacing all the
permissions. Select Yes, then OK, and OK again to close the
Permissions window.
You've now reset the permissions that should allow you uninstall the rest of the old components and install the new one.
Make sure that you install the x64 bit version of iTunes/Quicktime.