lol, format /mbr only fixes a broken bootsector (aka where ntldr/lilo starts from). Useful if going from Linux to NT/9x
Removing it from the boot sequence is in the read-only file boot.ini
Mark it RW and then delete the lines for Win2k Server, and it will work. Then you’ll have to manually blow away the Win2k Server files from the partition, but then you don’t need to worry about Win2k Server again.
Technically, ntldr, boot.ini and a few other files are actually in the MBR to very close to it, from my experience. Microsoft is kinda flaky on that issue of where they’re stored (actually I think it’s in both places, but that may just be me). The bootup option is preserved even if you run a standard format of the partition, such as if I were to reinstall NT Server then I’d have another NT Server listing, and the same with Windows 2000, XP and .NET Server 2003.