For either:
dd if=/dev/hda of=/dev/fd0 bs=512 count=1
or
dd if=/dev/hda of=/mnt/floppy/bootsect.lnx bs=512 count=1

Which bootsector am I saving? The lilo bs or the original windows one?

Either one saves the MBR of drive hda. The MBR is the first sector of hda. If the MBR is untouched, it will have the normal boot code in it. If lilo or grub is installed into the MBR, then it will be either lilo's or grub's boot code in it.

When you installed mandrake, did you have your windows drive connected as primary master and the linux drive as primary slave? Or did you switch them around when you installed linux? It sounds like you switched them around, because you said that linux would boot when connected as primary master.

If that's the way you did it, try putting the linux drive back as primary master and the windows drive as primary slave. Then boot into linux and edit the /etc/lilo.conf file and change the windows entry to:

other=/dev/hdb1
label=windows

Then run /sbin/lilo. Reboot.

If windows doesn't want to work, try changing the windows entry in /etc/lilo.conf to:

other=/dev/hdb1
label=windows
map-drive=0x80
to=0x81
map-drive=0x81
to=0x80

Then run /sbin/lilo and reboot.

may I recommend grub?

linuxcool: In the most recent installation I installed mandrake on hdb (primary - slave) and win2k was hda (primary - master). I did not install a bootloader at all but used the bootdisk instead. When both of the drives were plugged in, then windows would not boot, with the error 'Error loading operating system'. When I removed the hdb (slave/linux), then windows booted normally. After that I set both drives as master and installed lilo on the linux drive. Then to get into win2k/linux I just switched the ide cable from drive to drive having one plugged in at a time.

5amYan: If you may tell me how to configure it for dual boot, recommend away.

Make hda primary hdb slave
boot from floppy to Linux
su
/sbin/grub-install /dev/hda

should install grub

Then edit
/etc/grub.conf

# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You have a /boot partition. This means that
# all kernel and initrd paths are relative to /boot/, eg.
# root (hd1,0)
# kernel /vmlinuz-version ro root=/dev/hdb3
# initrd /initrd-version.img
#boot=/dev/hda
default=0
timeout=10
splashimage=(hd1,0)/grub/splash.xpm.gz
password --md5 $1$NðâD0Êfk$zYTwyN9E248KOaaqfXfSZ/
title Red Hat Linux (2.4.18-5)
root (hd1,0)
kernel /vmlinuz-2.4.18-5 ro root=/dev/hdb3 hdd=ide-scsi
initrd /initrd-2.4.18-5.img

title Windoze
rootnoverify (hd0,0)
chainloader +1

This will boot directly to Redhat. yours shouldn't be much different. but to say mandrake.

Try searching grub here on LQ!! It's been covered a couple times.
Still don't hesitate if you have a question.

Things are getting weird man
 

I bought a new IBM 80 giger so now i've got 2 one for win2k and one for linux. Ok. I installed lilo to the mbr, and all the settings are good. So I boot up the computer. And, it says
"
Booting from disk...
Booting from disk...
"
and then it stops and it keeps reading the fdd.

So how did I get into linux to post this?
No bootdisk. I'm not that smart.
Pissed, I put the Win2k SuperCD (amazing piece of work, if you use win2k I really suggest downloading it) and pressed esc (boot from mbr) and it gave me the lilo menu. That is fucl<ed up!?! Whats with the bios?

You might want to go into your bios and make sure the boot sequence is set to cdrom-->floppy-->hard drive. Make sure that your hard drives are enabled and that the primary master is the one set to boot from.

When you installed linux on the new 80gig drive, how did you connect it? Was it primary master or primary slave? During the install, you should have installed lilo in the boot sector of either the /boot partition, if you have one, or in the root ' / ' partition. When asked to make a boot disk, make one. Because you're going to need it if you want to set up linux to boot from the nt boot loader as explained at littlewhitedog.

I am just going to flash my bios with a newer version (mobo = EPoX 8kha+) .
I installed linux as a primary slave. I don't mind using lilo, at the time I didn't know that lilo could boot to win2k (ntfs). I'll post as updates present themselves. :D

funny i've never used LILO

I used BootX for PPC for years, then went right to grub.

OT sorry

Aight! I'm back in windows, I flashed a new bios up and set the boot order nice (cdrom-->floppy-->hdd-0). Lilo is working (great?). Thanks to everyone: linuxcool, MasterC, sarin, trickykid, 5amYan. Thank you. Time to start another thread.

Glad to hear you got it working and you're welcome. :)