Some of you have had problems installing Revit. Perhaps running the Program Install and Uninstall Troubleshooter via Microsoft Fix it portable will help?
I recommend using the following link. After downloading, you will have to run the exe, which itself will then download ‘Fix it portable’ to a folder that you select:
Portable Offline: MicrosoftFixit-portable.exe
In the top list, click on Install or upgrade software or hardware, and click ‘Run Now’ next to Diagnose and fix program installing and uninstalling problems automatically.