itunes will not open

Itunes will not launch (Quicktime does). No error messages.

I have searched the forums and boards and done the following:

I have End Process Itunes in Processes, no change.

I have disabled and enabled Bonjour.

I have removed Advanced Systems Care

I have uninstalled, downloaded and reinstalled Itunes. (3x)

I have used the msconfig suggestion/reboot

Administrator Account is all that is turned on.

I have scanned for virus with Avast - none.

Out of options.

Icon does appear with User Account Control on Win7 desktop which in the past it did not require.

Suggestions welcome.

david