missing or corrupt: System32\Drivers\Ntfs.sys

my second compute decided to spit out this error:

Windows could not start because the following file is
missing or corrupt: System32\Drivers\Ntfs.sys

now microsoft tells me that it is caused by changing the
hard disk to NTFS system.. (didn't do that).

they tell me to fix the problem all i have to do is put in
my windows cd and hit "r" on the "Welcome to Setup"
screen.. problem being.. The ntfs.sys error prevents me
from getting to that screen, so I can't hit "r".

thus far the only things i can think of are trying to get
it to boot up in dos (hasn't happened yet) and replace the
file.. or scrap the HD, and start over (not a good option).

Need all the help i can get.

TIA.