This solution not working for me. Cannot see my devices in iTunes

I have tried uninstalling and re-installing iTunes MANY times over the last week and STILL cannot get itunes to see my ipod or iphone. I have downloaded the latest version, I have tried turning off Microsoft Essentials, I have tried installing old versions of iTunes first and upgrading. I have run the program CCleaner after uninstalling to clean off any remaining files.

I have found that when iTunes 10.6 was installed the Apple Mobile Device Services is not listed in Services and manually trying to install that fails and "rolls back".

I had installed 10.6 and when I tried to upgrade to 10.7 I get the following messages.

iTunes Installer Completed

The installer encounted errors before iTunes could be configured,

Errors occurred during installation. Your system could not be modified.

Please run the installer again, or click Finish to exit

I am running Windows 7.

Any help greatly appreciatted.