a couple of days ago I decided I'd better run sfc don't recall why
but I got the error cannot load windows resource protection
later I read how to run sfc offline
I booted to my vista 64 bit home premium with sp2
I chose system repair, then the the command prompt
I tried sfc /scannow /offbootdir=e: /offwindir=e:\windows my dvd is e
that ran sfc but said it found errors it couldn't correct (some it did I guess)
it had a log file which was mighty big and half the time it won't let me access it
interesting I was then able to run sfc like normal after booting.
and it found no errors

does that make sense to anyone?