Para se conectar ao Wifi, você pode seguir a seguinte resposta no SE:
Conectando-se à rede wifi através da linha de comando
Então você deve conseguir reinstalar o KDE.
Além disso, para desinstalar o VLC, você pode usar
sudo apt purge VLC
ou
sudo apt-get purge VLC
O comando de acordo com a página man:
sudo apt-get autoremove
autoremove is used to remove packages that were automatically installed to satisfy dependencies for other packages and are now no longer needed as dependencies changed or the package(s) needing them were removed in the meantime.
You should check that the list does not include applications you have grown to like even though they were once installed just as a dependency of another package. You can mark such a package as manually installed by using apt-mark(8). Packages which you have installed explicitly via install are also never proposed for automatic removal.