I am running Mandriva 2009 Spring on a Dell Latitude E6500 with Nvidia graphics. I had it running for a couple of days when the screen locked up for a while & pretty soon a message popped up that composting had crashed or locked up, something to that effect. When it finaly started responding, my apps were still running, but the desktop was gone, just a checkered background with some red squares with an x in the middle. If you right clicked on them, they give the option to remove the unrecognized widget. The desktop is checkered. There is no panel whatsover. When I restart the computer or logout & back in, the graphical login comes up & everything looks normal until it says, "Starting Windowmanager", it then fades to the checkered background. How do I get the windowmanager setup again? Thanks

Open your System Settings (if you are running KDE4 desktop) then go to Default Applications in there select Window Manager from the list. Choose the Default Window manager Kwin. If the change doesn't happen straight away, log out then back in again. If you still continue to have problems, disable Desktop Effects under the Desktop icon. Log out, then back in again. Let us know how you get on.

Again, if you are running KDE4. The System Settings is (if you are using the default icon theme) the Wrench & Screwdriver icon

As I mentioned in my post, the menu is gone. Can you give me the name of the applet so I can kick it off from the command line? Thanks

I found the command, systemsettings, but when I go to Default Applications & Window Manager, Kwin is selected & the option to select another one is greyed out. I wonder if kwin is the only one installed, I'll have to check that.

If you can still get a run box using Alt & F2 type: systemsettings to start the settings app. To try and restore your panel, type: killall -9 plasma to make sure it's not running, then type: plasma see if it starts back up.

In that case I would disable desktop effects and see if that makes a difference.

When I tried to restart plasma, I get the following results:

could not access kephald, falling back to QDesktopWidget
adding an output 0 with geom: QRect(0,0 1280x800)
adding a disconnected output 1
adding a disconnected output 2
adding a disconnected output 3
kdeinit4: preparing to launch /usr/lib/kde4/libexec/klauncher
kdeinit4: preparing to launch /usr/bin/kded4
kdeinit4: preparing to launch /usr/bin/kbuildsycoca4
kbuildsycoca4 running...
kdeinit4: preparing to launch /usr/bin/kbuildsycoca4
kbuildsycoca4 running...
kbuildsycoca4(23282)/kdecore (KService) KServicePrivate::init: The desktop entry file"/usr/share/applications/kde4/trash.desktop" has Type= "Link" instead of "Application" or "Service"

kbuildsycoca4(23282)/kdecore (KService) KBuildServiceFactory::createEntry: Invalid Service : "/usr/share/applications/kde4/trash.desktop"
kdeinit4: preparing to launch /usr/lib/kde4/libexec/kconf_update
kdeinit4: preparing to launch
kdeinit4: preparing to launch

I also tried enabling & disable 3d effects which did not help.

As you've only had it running for a couple of days I doubt whether you have made any major changes to the default desktop. I recommend you reinstall.

If you want to keep your old settings (which I advise against) then choose use existing partition when you are asked how to install.

Then at the repartition stage don't format /home only /. (this way you will retain any documents and other files in your home folder) keep the same username.

If on the other hand you just want it from fresh, choose use existing partition and click your way through the wizard until reinstallation starts. (this way you lose everything)

Before performing a re-installation of Mandriva, try renaming the .kde4 directory to (perhaps) .kde4-bac, then restart the system (You do not have to actually restart the system, but it is the simplest way to accomplish what is needed here). If Mandriva restarts to the GUI with a working desktop, the issue was with some KDE setting. If not, a full re-installation may be the next logical step . . .