hi, you can try unattended, this projekt lets you pxe-boot an linux-system purposed to install windows on any computer connected to lan. it works just like "knoppix-pxe-server" in /tftpboot you need unattended-kernel and initrd, i386-directorys of your orig. Windows Install CDs. em, i made win 2ksp2 2ksp4 and xp installation availeable, don't know if it supports vista... and you should add unattended-kernel to your configfile /tftpboot/pxelinux.cfg/Default

but... have a look at their howtos:
http://unattended.sourceforge.net/step-by-step.php
http://unattended.sourceforge.net/advanced.php#netboot

ok it IS a bit more tricky than just getting pxe-boot to work... but the only way i know to perform windows-lan-installation

better you install this to your local server, instead of knoppix
and try pxegrub instead of pxelinux