dell latitude wont boot up?

My dell latitude laptop was slow to boot up, so i cleaned out the registry using ccleaner, i also defragged?
i defragged the disc, when i turned the laptop on, it took a while to boot then a blue screen came up saying 'checking file system on c:'
there are 5 stages in the process, it got as far as stage 4 but then it froze at 3% of stage 4.

recently the laptop freezes when shutting down, please help.
the point is the laptop is not starting. please some body help me, i really need to get this working before monday, all my assignment are on it & they are due for tuesday.
please help me. i'm freaking out.