more information needed..

which apple model? osx version? was it xp or win7 or win8?
what were you doing before these error come up? have you install anything recently?

me pretty sure someone will help if you could at least provide these information..

without knowing these information, i would suggest you to
1. hit ctrl-alt-del
2. press command-R
3. work from whatever options presented to you here

hope this help. cheers