By Bootscreen he means the black screen with the Windows logo and the blue loading bar at the bottom. The one you see before the welcome screen.
There's a good program you can use to switch bootscreens on this page:
http://userxp.belchfire.net/ . Use that - it's the simplest way.
NTFS.sys shouldn't have been touched. If you can't boot into Windows now - you'll have to do a repair of XP. If you can boot into Windows, maybe a system restore will help solve the NTFS.sys problem