Installing Dual boot

you should edit the boot.ini file usualy in c:\drive (hidden) it should look somthing like that:
timeout=30
default=c:\
[operating systems]
multi(0)disk(0)rdisk(0)partition(2)\WINNT="Microsoft Windows 2000 Advanced Server" /fastdetect
multi(0)disk(0)rdisk(0)partition(1)\windows
than uninstall Bootmagic and if you will have any problem with mbr boot from win2k cd
and sekect cmd cons / fix mbr option

Boot from the cd, use repair, choose console.
in the recoveryconsole use fixboot and fixmbr.

Good luck.

Read your boot.ini file, you say it says:
[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINNT
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINNT="Microsoft Windows 2000 Advanced Server" /fastdetect
C:\CMDCONS\BOOTSECT.DAT="Microsoft Windows 2000 Recovery Console" /cmdcons

So, from this we can deduce that your default OS is on disk 0 (Primary Master) partition 1, you get the option of booting to on OS, which is on disk 0, partition 1. So, now thatwe have this figured out we need to answer some questions. When you installed Windows 2000 Pro and Windows 2000 AS, where did you install them? Was it on separate partitions? Did you rename one of the install locations as Windows instead of WINNT? When you install a dual-boot with Windows, it is best to load your primary OS first on your first partition, and your alternate OS second on your second partition and ensure that both root directories have a unique name, like WINNT and WIN2KAS, orwhatever tickles your fancy. This will help you down the road anyways, to help you keep the two separate in your mind. When configured properly, your boot.ini should have two of the multi(0)disk(0)? lines, one will say Advanced Server, the other will say Professional and each should point to the proper directory. I am guessing that you installed both to the WINNT folder on the primary partition. I would start from scratch so you know it is done right, reformat the hard drive (I would use NTFS), divide it into at least two drives (you will hate yourself if they are smaller than 4 GB each, I suggest 8-10), install Win2K AS first, then Win2K Pro on your second partition.