How do I fix conflicting packages on Slackware 14.2 after making a mess with installing a program in different versions?

I installed ffmpeg-3 and ssr-0.3.11, both Slackbuilds packages, but as the codecs were not working, I decided to install the most current versions of the sources, from both programs. It didn't work anyway, so I uninstalled it. To make the mess worse, I installed an older ffmpeg later, 2. It didn't work. After that I reinstalled the versions of Slackbuilds, but now the simplescreenrecorder (ssr) does not open because it says that it did not find libavformat.56; but ssr needs libavformat.57, so there is something wrong there and I can't undo this mess. Is there a program for Slackware that looks for conflicts and tries to solve this kind of mess?