Windows 7 - 64 bit Geforce GT 640
Broken: Testbuild2 2.78
Short description of error
The installer quits because it says a newer version of Blender is already installed. I've only installed 2.77, so apparently the installer detects 2.77 as being newer than 2.78 testbuild 2
Exact steps for others to reproduce the error
Based on a (as simple as possible) attached .blend file with minimum amount of steps
Have 2.77 installed on your computer, download
press 'install' and then wait for the error message to pop up.