How to fix boot sector error?

I am a newbie here guys and I have a great problem with my PC. Recently, when I was trying to start my PC, a message has popped out. The message says that there is a boot sector error and need the disk to setup or recover. Then, I tried to recover it with Ubuntu live CD and I saw that there is only one partition there. That even applies to my total hard disk.
What should I do?
Thanks friends.
