can't create restore point

[none]

I'm helping someone with a XP home system that we can't
create a restore point. We have system restore enabled and
have 70GB of free space, but when we click to create the
restore point it says it can't and says to restart and then
try again. Restarting changes nothing. I searched for
help and saw an article on the identical problem, but only
in ME. It suggested renaming wininit.ini in safe mode,
then restarting in normal mode. I tried that and it made
no difference.