Suse doesn´t boot to KDE 4

Hello,
I am new to Linux and installed SUSE 11.1 yesterday with KDE 4. My Problem is, that SUSE doesn´t start KDE after boot. And if I go to runlevel 3 and type “startkde”, I get the message “$DISPLAY is not set or cannot connect to the X server.”

How can I start KDE and how can I set KDE as standard?

Does this mean you are logging in from a terminal (no graphic login)?
If so, what display card have you got?
If it’s ati, you need to install the ati drivers manually. If nvidia, go to yast (it will run from terminal) and add the nvidia repo and install the nvidia drivers.
To configure the display, run sax2 as root from the terminal and configure the display.

Well, I reinstalled and now KDE is running directly.

Thx for support!