Windows 2000 Server SAM File

I need to replace the SAM file of a Windows Server 2000 machine. But I can't do it while it's running the OS as the SAM file is being used. I can only do it by running the machine on DOS and loading the NTFS volumes i.e the C drive etc.
How can I go about doing this, any leads?

These 2 freewares can move or delete locked files before windows boots. But I've never used them to replace SAM. So use with caution.

www.snapfiles.com/get/moveonboot.html

www.gibinsoft.net/gipoutils/bin/moveonb.exe

Or you could probably boot off of a Linux Live CD and copy/replace it that way.