Ok so you have linux already installed and win2k already installed but they are on separate hardisks? Ideally you would not set-up linux until after you had win2k pro installed. Then during the linux install process for you would specify to activatethe lilo bootloader on the root partition of the win2k harddrive. this will cause the bios to call the lilo bootloader first which would then read the linux lilo.conf from the boot sector of linux and this would present you with your choice of op system. choosing win2k pro would send the boot process back to normal win 2k boot process choosing the other ways completes linux bootup.
All this is necessary since windows doesnot support linux under any condition, in fact make sure you have an emergency boot disk for linux cause if you need to fix win2k it will destroy the lilo bootloader and put back the win2k single op system one.
Since you already have installed linux and i presume have valuable info you don't want deleted, start the install for linux in expert mode but choose repair and pray you remember which partitions you set on hdb drive so you can just choose to update software and install lilo.
best regards rick