There is an abundance of help right here. You will need to provide a lot more detail though. I assume you are citing a specific error message. Exactly what do you do to get that message? What is the exact message? What changed or what happened just before the message started appearing? What is displayed leading up the appearance of the message?
Some description of the computer may be useful.
I will take a wild guess that it happens when the BIOS tries to find a bootable disk. It may mean that your disk has been corrupted or is faulty.
Last edited by theNbomr; 11-03-2012 at 12:20 PM.