Currently Being ModeratedMay 26, 2012 1:09 PM (in response to ira7420)
I was trying to just update iTunes, but it told me that it can't find Bonjour.msi. So I tried to uninstall the file/program Bonjour 1.10MB (which looks like a blank page, not the actual icon). Windows Installer says this; "The installation source for this product is not available. Verify that the source exists and that you can access it."
To install the utility, doubleclick the msicuu2.exe file you downloaded.
Now run the utility ("Start > All Programs > Windows Install Clean Up"). In the list of programs that appears in CleanUp, select any Bonjour entries and click "Remove", as per the following screenshot:
Quit out of CleanUp, restart the PC and try another install. Does it go through this time?