It's odd that you would have two installations of the same version of Lightroom 5. On Windows, installation of an update normally replaces a previous one. A new major version such as Lightroom 6 would be installed in addition to an older version. At any rate, each version of Lightroom is separate and independent. There is nothing in a previous version the program file that is needed. The newer version would use the same catalog and previews, etc. But the program itself can be removed using the Windows uninstall routine.
I thought it was odd that I had two versions of Lightroom installed as well. I have been able to track the issue back to an apparent "bug" in the Lightroom 5.2 update that installed a second version of Lightroom in addition to updating the existing version on my computers. At the time, I posted about it at Lightroom 5 installed twice on my laptop. While I never got an answer to my question, which was "Is this normal?" I did hear from others in the forum the experienced the same problem and had the same question. As time passed, later releases updated one of the two installations, but did not effect the second. Hence, two different versions of Lightroom 5 installed on the same computer.
Uninstalling the older version solved the problem. Thanks