I was curious, so I installed kde alongside gnome (which I use primarily, for the matter).I am running arch linux, and I installed kde using yaourt, by the following command:yaourt -Syua # update databases  yaourt -S kde --force # install kde itselfI installed everything yaourt suggested for kde, and I didn't get any errors.So, I rebooted the computer, selected kde plasma in the gdm environment select menu. I entered the password and gdm accepted it.However, when gdm starts kde, I see a wallpaper with a white transparent rectangle with a picture of a hard disk on the left. The mouse is visible and I can move it, but that's it. Nothing happens after that.Is this normal or do I have to re-install kde ?
First KDE Session
arch linux;kde;desktop;gdm;yaourt
This is not normal, it is clearly a KDE configuration problem. Unfortunately, most linux distributions doesn't works a lot configuring its KDE, practically that are only compiling that and uploading into their package archive without any deeper test. It is not in their main scope. :-(Although in most cases you can easy handle such problems. KDE is only a collection of a lot of X programs, mainly the kwin window manager and the tray application, and yet a lot of them. They all are using the Qt toolkit which is a very powerful and interesting technology. Fortunately, we have also a trivial script which starts all of the needed tools to a KDE session from a command line. This is named as startkde. It is wasn't started by your gdm (probably it wasn't configured properly), you can do this by hand.Open a character console with the same user as your X user (alt/ctrl/f1), and enter a DISPLAY=:0 startkde & command. This startkde initiates the normal KDE boot sequence from command line.If it further doesn't work, I am waiting your comments. If it works and now you want to automatize that, I am waiting your next question.If there are problems, there is a simpler way if you start only kwin instead of startkde. It will open only the window manager, not a whole session, but it will maybe work.Alternatively, you could try another distribution with real KDE support (I suggest OpenSUSE or Mint).