I got this gem of an error tonight while installing SQL Server 2014 Express (just trying to get the management studio mind you but having to install the whole package):
Error installing SQL Server Setup Support Files
An error occurred during the installation of assembly 'Microsoft.VC80.ATL,version="8.0.50727.6229",publicKeyToken="1fc8b3b9a1e18e3b",processorArchitecture="x86",type="win32"'. Please refer to Help and Support for more information. HRESULT: 0x80070BC9.
Error code: 1935
This error can occur for multiple reasons. One has an easy fix, one has more detailed fix.
The first (and easiest to fix) is if you have a pending Windows Update reboot (one that auto-installed but hasn’t rebooted yet). This is the easy fix, reboot and let Windows Update finish updating. After the reboot you should be able to continue your install. I assume something in the Windows Update conflicted with the SQL Server install.
This can also apparantly occur if the Microsoft.VC80.ATL file becomes corrupted. If this is the case you'll have to repair the installation
For posterity, here are the steps.