I recently upgraded PclinuxOS (using commands apt-get update, then upgrade and finally dist-upgrade). The process went all right and about 500mb of data was downloaded, as I had not upgraded this installation for some time. On rebooting, however, there was a very simple localhost login screen. On logging, only 2 simple terminal windows appeared on a black screen. I could write commands on the windows and could even start firefox. But firefox window did not have any close buttons and I had to shut down power to reboot. Why is KDE4 not starting? The command startkde does not work. How can I correct this problem? Thanks for your help.

Have you checked the disk space?
Is it sufficient?

Try to fix broken packages and restart it again.

PCLinuxOS may be booting to runlevel 3 (multi-user, text mode). Try issuing the command "init 5" (without quotes). If it's successful, KDE should start up and present the login screen.

Then you need to look at /etc/inittab. Look for # The default runlevel. If it says something like id:3:initdefault:, change the 3 to 5 and save the file. Subsequent boots should boot to GUI mode.

As bloodstreetboy points out, if you don't have enough disk space to load the graphics files, KDE can't start up.

There is no space problem. There are no broken packages. I have run commands "apt-get check" and "apt-get upgrade --fix-broken" also.

Runlevel in initab is 5. It is not booting to text terminal. It is booting into a very simple window manager GUI mode with 2 xterm/konsole/lxterminal like windows where I can enter commands. However, KDE proper is not starting.

Try to reconfigure or reinstall kde.
www.youtube.com/watch?v=xeD5swDkV9c‎

Have you tried selecting KDE from your session menu on the log in screen? From what you've written it sounds like you're running in failsafe and I've never heard of PcLinux doing that unless it was selected by the user.

You could also try booting to a command line session by pressing "f1" then "f1" again then "e" then "e" again to edit the grub entry then adding a "space" then "3" to the end of the kernel line then press "enter" them "b".

Make sure to use a direction key to stop the auto launch and make sure pclinux is highlighted before you start editing the entry. This will put you in a terminal session with no GUI one time only, from there you can try startkde again.

Thanks for your suggestions. I tried 3 at the grub kernel line and booted to commandline. There is no startkde command. There is kstart command which gives an error: "cannot connect to X server". This occurs both as root and as non-root user. There is also startx command which uses .xinitrc which has 'exec startkde', hence it gives an error: startkde not found.

If you are facing this error, take a look at this.
http://www.linuxquestions.org/questi...-found-256432/
&
http://www.kubuntuforums.net/showthr...quot-not-found

I know it's a little late but with PcLinux never use apt-get upgrade, only use apt-get dist-upgrade. Using apt-get upgrade will always break your system,sometimes immediately sometimes with later upgrades but it always causes problems.

You can try running apt-get update then apt-get dist-upgrade then apt-get install task-kde, it may get your KDE back up but you should consider a reinstall if you ran apt-get upgrade.