Google it.
NT loader program. Sometimes you can fix it with an installation CD. Sometimes it is a little tricky. Can't recall how I fixed it years ago before start using Ghost.
http://www.tinyempire.com/shortnotes/files/ntldr_missing.htm
http://www.lockergnome.com/blade/2006/12/12/ntldr-is-missing-how-to-repair/