The message probably means that the hard disk has failed and needs to be replaced. What it the EXACT
message on the screen?
After replacing the hard drive you will need to buy a new copy of Windows so you can install it on the computer. Sometimes the manufacturer will sell you a pre-formatted hard disk with Windows installed. Or they might offer to sell you a cheaper Windows recovery DVD.
If the laptop was advertized as a fully working unit Ebay should return your money.