installed knoppix hdb and win2k on hda1 is now unbootable

[Markus]

Now if this is the case, then lilo (the linux loader) is installed on the MBR (master boot record) of your hdb hard drive -- the loader for windows should be intact on your hda hard drive.

lilo should be in the MBR of hda. Have a look in /etc/lilo.conf:
# Specifies the boot device. This is where Lilo installs its boot
# block. It can be either a partition, or the raw device, in which
# case it installs in the MBR, and will overwrite the current MBR.
#
boot=/dev/hda

To be able to boot windows you need a section like:
other=/dev/hda1
label="Windows"

Hmm, I might as well post my whole lilo.conf as I have windows on hda and linux on hdb:

# /etc/lilo.conf - See: 'lilo(8)' and 'lilo.conf(5)',
# ---------------       'install-mbr(8)', '/usr/share/doc/lilo/',
#                       and '/usr/share/doc/mbr/'.

# Support LBA for large hard disks.
#
lba32

# Overrides the default mapping between harddisk names and the BIOS'
# harddisk order. Use with caution.
#disk=/dev/hde
#    bios=0x81

#disk=/dev/sda
#    bios=0x80

# Specifies the boot device.  This is where Lilo installs its boot
# block.  It can be either a partition, or the raw device, in which
# case it installs in the MBR, and will overwrite the current MBR.
#

boot=/dev/hda

# Specifies the device that should be mounted as root. ('/')
#

root=/dev/hdb1

# Default menu for Debian. (Using the images from debian-bootscreen)
# from Philipp Wolfer <[email protected]>.
bitmap=/boot/debian.bmp
bmp-colors=1,,0,2,,0
bmp-table=120p,173p,1,15,17
bmp-timer=254p,432p,1,0,0

# Install the specified file as the new boot sector.
# LILO supports built in boot sectory, you only need
# to specify the type, choose one from 'text', 'menu' or 'bitmap'.
# new: install=bmp      old: install=/boot/boot-bmp.b
# new: install=text     old: install=/boot/boot-text.b
# new: install=menu     old: install=/boot/boot-menu.b or boot.b
# default: 'menu' is default, unless you have a bitmap= line
# Note: install=bmp must be used to see the bitmap menu.
# install=menu
# install=bmp
install=bmp

# Specifies the number of _tenths_ of a second LILO should
# wait before booting the first image.  LILO
# doesn't wait if DELAY is omitted or if DELAY is set to zero.

delay=20

# Prompt to use certaing image. If prompt is specified without timeout,
# boot will not take place unless you hit RETURN
prompt
timeout=50

# Specifies the location of the map file. If MAP is
# omitted, a file /boot/map is used.
map=/boot/map

vga=normal

default="Windows2K(hda1)"

image=/boot/vmlinuz-2.6.9-291204
        label="Linux-2.6.9"
        append="ramdisk_size=100000 lang=us hda=scsi hdb=scsi hdb=2434,255,63 nomce "
        read-only

image=/boot/vmlinuz-2.6.7
        label="Linux-2.6.7"
        append="ramdisk_size=100000 lang=us hda=scsi hdb=scsi hdb=2434,255,63 nomce "
        read-only

other=/dev/hda1
        label="Windows2K(hda1)"