Same Deal. Installed 64-bit Windows version of Blender 2.80 to C:\Program Files\Blender Foundation\Blender\2.80, and it wiped out the 2.79 version installed at C:\Program Files\Blender Foundation\Blender\2.79, including the "2.79" sub-folder of C:\Program Files\Blender Foundation\Blender\. I need to run both versions until all previous work is converted to 2.80 or other platforms, including interactive BGE (Blender Game Engine) apps.