By default, Audacity 4 installs itself to C:\Program Files\Audacity 4 while Audacity 3 and earlier installs itself to C:\Program Files\Audacity. So yes, they live fine side-by-side, and you can even have both running at the same time.
By default, Audacity 4 installs itself to C:\Program Files\Audacity 4 while Audacity 3 and earlier installs itself to C:\Program Files\Audacity. So yes, they live fine side-by-side, and you can even have both running at the same time.