Recovering ntfs.sys file using Knoppix

A friend of mine had a problem with his laptop last week. Apparently after he rebooted, the ntfs.sys file got corrupted and so now can't log into Windows (XP, by the way). Last year I had a similar problem, only that it was some dll required for logging in. Since I'd never used Knoppix before (though I was a junior in CS at the time), my step-brother booted it up and copied the file from my Dell recovery partition (which he also has). Since this was around Knoppix 3.2 or so, he had to do something like mounting the NTFS onto Knoppix (I'm not really sure since he did it while I was out of the room). Anyway, does anyone know how this might work in my friend's case? My concern is that Knoppix uses the ntfs.sys file for writing to an ntfs partition (right?). Sorry to be bugging you, but he wants this done before he goes back home for the summer next weekend and I'm simply too bogged down with senior projects and whatnot. Any help would be appreciated.