For all those having issues with the 11.1.4.62 update
The issues encountered are vast... msvcr80.dll issues.. Apple Mobile Device failed to start... and on and on... Never understand how a simple update can completely screw up everything and make iTunes unusable.
Go into Programs and Features and ANYTHING that says "Apple" with something after it, uninstall it.
Reboot
Download a fresh copy on iTunes
Right click on iTunes64Setup.exe left click on Run as Administrator. Even if you're only use on your computer and it's an Administrator account do it.
Cross your fingers, throw some salt over your shoulder, say a prayer. If the install completes with no error measages you're done.
If you still get the msvcr80.dll error
Google How to use scannow Windows 'Whatever Version you're running'
This will check the integrity of your system files.
If everything checks out you need to replace the missing dll file
Use Google again for Missing msvcr80.dll
I had to put the dll back in Windows/System32/ for iTunes to install properly.
Windows 7