First thanx for reply!

These are the messages I get when I start from DVD:

Darwin/x86 boot v5.0.132 - Chameleon v1.0.11
Build date: 2008-06-09 20:12:22
VESA v3.0 14 MB (NVIDIA)
Press any key to start...


And then:

Loading Darwin/x86
Loading kernel mach_kernel
Loading HFS+ file: [mach_kernel] from 4230a80.
Loading HFS+ file: [mach_kernel] from 4230a80.
LoadingDrivers: Loading from/System/Library/Extensions.mkext
Loading HFS+ file: [/System/Library/Extensions.mkext] from 4230a80.
Loading HFS+ file: [/System/Library/Extensions.mkext] from 4230a80.
Starting Darwin/x86

Now the screen gets black, the installation stops, the computer restarts.
I hope you have an idea, what I can do.
Greetings!