Yes, I want. I've done, what Puttabong wrote and now at boot it says something like: windows is broken, launch windows-dvd ...
But Leopard doesn't boot. What shall I do?

buy an IDE HD for OS X ;) Is the safest way.

Oh, I haven't seen roisofts instructions.
... will be in second ;-)

look my previous post..

Great. Now Leopard Bootmanager starts. I typed nothing ... -> kernel panic, I typed cpus=1 ... -> freezes after loading kexts, I typed -x ... -> loading kexts, after that reboot
!?

What does the Kernel Panic tell us? Make a Picture of your Screen, please.

GeForce kexts again? How about booting with or without -legacy? tried platform=ACPI or platform=x86pc? You can also combine the options.

Ok, wait ehh... a second ... or two. ;-)

boot with -s

and type

mount -uw /

rm -r /system/library/extensions/Nvdaresman.kext

Ok, the screen when I boot without any flag and with cpus=1