STOP disk check

How do I stop disk check from running? I started about 3 hours ago, and it's only about 70%, so I turned off my computer (ESC key didn't work, ALT CTRL DEL didn't work). When I turned it back on, the disk check started from 0% again. I tried this twice to no avail.

I've been chatting online for about 10 minutes but it seems the guy cannot help. He put me on hold fro "consult his resources".

I cannot afford to lose the whole day waiting for it to finish.

PLEASE HELP......

Thank you!