hello,
here I go with one more problem :/
after installing hardy, I wanted to install firefox (as there was no firefox directly in the menu "Internet" and I couldnīt find it nowhere). so I downloaded it, but the script just wonīt run (right click - run as root .. nothing happens, no error displayed). so I desperately typed in konsole "apt-get install firefox". this time, the system responded by removing all possible packages (why???) then installing it again and asking for reboot. that was the last time I saw the xserver running.
next time, only the command line interface was at disposal. while trying "X" command, I got a screen with a cross instead of a cursor, and all I can do there is to turn the computer off (with button). I simply donīt get why I always finish with problems concerning xserver when performing such a simple task as installing a new software. every time I install a new version or reinstall it on another computer, I spent more than a week fixing various problems such as this one. please help!!
thanks for any ideas!

ps: I also tried removing the file /tmp/.X0-lock, but it didnīt help.