When I look at my control panel the only program that shows is "I Tunes". No other supporting programs are showing up in the control panel nor the Common Files nor in the Program Files (x86).
That's an extreme case of this.
We'll try doing standalone installations of all the supporting programs.
Download and save a copy of the iTunesSetup.exe (or iTunes64setup.exe) installer file to your hard drive:
Download and install the free trial version of WinRAR suitable for your PC (there's a 32-bit Windows version and a 64-bit Windows version):
Right-click the iTunesSetup.exe (or iTunes64Setup.exe), and select "Extract to iTunesSetup" (or "Extract to iTunes64Setup"). WinRAR will expand the contents of the file into a folder called "iTunesSetup" (or "iTunes64Setup").
Go into the folder and doubleclick the AppleApplicationSupport.msi to do a standalone AAS install.
Doubleclick the AppleMobileDeviceSupport.msi (or AppleMobileDeviceSupport64.msi) to do a standalone Apple Mobile Device Support install.
Doubleclick the AppleSoftwareUpdate.msi to do a standalone Apple Software Update install.
Doubleclick the Bonjour.msi (or Bonjour64.msi) to do a standalone Bonjour install.
Do those four installs go through okay? If so, does your iTunes launch without any errors now?