You never need to do that.
If you need to dink around with your installation, you plonk another copy of NT on the box - ideally on a different drive - and then boot that up to do yer doin's. This has the added advantage of allowing you to run with a filesystem that isn't glass-fragile and does actually support security.
Anyone who kept their servers on FAT for "recovery purposes" didn't have a decent recovery plan in place. Hacking around in %SYSTEMROOT%\\Drivers with a DOS boot disk on a production server indicates a lack of forethought and specifically a lack of backups.
The Windows 2000 Server CD is bootable and has a facility called the Recovery Console which allows you to perform maintenance on your installation.