As for the removal, there are nuances:
— a simple uninstall (apt-get remove) removes the application files, but does not remove the settings (similar to windows not cleans the registry, and program files is not always completely some settings.dat will be), that is, by installing the application the next time you get the same settings that were
— complete uninstall (apt-get purge) removes all the program and settings
— automatic cleaning (apt-get autoremove) — remove no longer needed packages (the ones that were pulled for dependancies to other, already deleted, packages and more the system does not use)
Verify the integrity of dependencies apt-get check — it can help in case when installing/removing emerged of a fatal error
Synaptic package Manager too, as it supports these commands
To check the rendering (maybe the driver did not stand up) with the command "glxinfo" ("glxinfo | grep render" — skip a bunch of technical information) — must be the string "direct rendering: Yes" and the string is somehow related to the GPU, to estimate the speed at the "glxgears"
PS I'm in Windows I do not know where that is written when you install/run the application, it was necessary to put the type of program Ashampoo Uninstaller and/or FileMon/RegMon such unexpected places at times came across that the "knee" of the trousers that the "true" program from MS