Showing black screen

Looks like your master boot record is corrupted on the working hard disk drive.
If you have a windows xp disc pop it into your cd drive and boot from it, you can repair the boot record by going to the command prompt of the repair option, once your there type Fixboot,and press enter. After that type fixmbr,and press enter.
Then reboot the pc.

Thanks for the reply but sill am not able to resolve the problem,when i inserted a xp setup cd it asked "press a key to boot from cd",and after that screen goes black again.Many recommendation came for alteration of SATA port.but I donno exactly what to do..