Q: cannot install quicktime (later version already installed)

I was having trouble with the updater for iTunes and Quicktime. It would update iTunes, but never update Quicktime. The next fault was that it would install neither and would go into a loop i.e. when I click on update all, it would go back to the update start screen again.

I uninstalled both iTunes and Quicktime, and downloaded the latest versions.

My problem is as follows. 1)When I try and install iTunes, I get a message that Quicktime needs to be installed first. 2)When I install Quicktime, I get a message saying that it cannot install because a later version is already installed.

I have cleaned out all references to iTunes, Apple Software Update, Apple Mobile Device Support, iCloud,  Bonjour, Apple Application Support from all folders and also cleaned out any references in the registry.

When I try to install Quicktime, I still get the error about a later version already installed.

What should I do to find out what is causing this error?

I'm using Windows 7 Pro (32-Bit)