Removing broken computers Lightroom 6.0 installations

Hi

I tried searching, but didn't find any answers even I think this is already discussed.

System info:

Lightroom version: 6.0 [1014445]
License: Perpetual
Version: 6.3 [9600]

I have used this version long time, but it still serves me fully. But now I would like to install another Lightroom to my laptop and Lightroom installation says that I have three active Lightrooms. I have installed it three times, but as my two previous laptops have broken, I can not uninstall those.

So, what needs to be done, so I can install Lightroom to my second computer? It's not CC version, so there is no active lisences to remove from the website.