SOLUTION to THE WINDOWS INSTALLER SERVICE COULD NOT BE ACCESSED...Vista x64

I spent the better part of a month looking for the solution to this. My mom recently purchased a new computer that came with Vista Home Premium (64bit) preinstalled. Although we were able to install all of her other programs that were 32 bit, when we downloaded the 64bit Itunes from the website we received the error:

"The Windows Installer service could not be accessed, This can occur if you are running Windows in Safe Mode, or if the Windows installer is not correctly installed. Contact your support personnel for assistance."

I tried everything from unregistering and then re-registering the msiexec files in both the system32 folder and the sysWOW64 folder. I tried editing the registry and changing the windows installer imagepath to the SysWOW64 folder. I tried running it with UAC on and then off and from the true Administrator account, etc....nothing solved the issue.

Finally, the other day I was searching the problem out and came upon this blog:

http://blog.thinksharp.nl/

I changed the key

HKEY LOCALMACHINE\SYSTEM\CurrentControlSet\Services\MSIServer\WOW64
from a 1 to a 0.
I then stopped and restarted the Windows Installer Service by using services.msc.

After this approach, Itunes and quicktime finally installed without a hitch and my mom is finally able to use her Ipod again.

Just wanted to post this as it might help others that are having the same problem. There are many postings elsewhere on the net about this issue with just as many solutions...none of which worked for me except this one.

Thanks!