From Windows 2000, you can select which OS will be default by editing the boot.ini (as in NT4) or by right clicking and selecting My Computer / Properties / Advanced / Startup and Recovery / Set Default operating System
In a dual boot situation (or you install Windows NT on to NTFS partitions created by Windows 2000), you must be aware that Windows 2000 NTFS supports capacities unavailable to the Windows NT NTFS. Windows NT SP4 or later can function in the dual boot environment but the Windows NT chkdsk or autochk.exe can not repair the Windows 2000 NTFS. An attempt to run the Windows NT chkdsk against the new NTFS will result in
My Computer / Properties / Advanced / Startup and Recovery / Set Default operating Systempulldown
Err Msg: This Drive Cannot Be Checked with this Version of ...