NX9010 won't boot even though hard drive appears fine!

A friend of mine just gave me an HP NX9010 notebook, the thing appears to be in perfect working order, it turns on fine, everything is detected fine, etc. However when it comes to booting it simply says 'Operating system not found' .

I can boot the computer using a bootable CD and there are no problems, the hard drive is detected and all the files were intact. I attempted to re-install windows, but after this installation process it was still hitting me with the 'operating system not found' error message. What the hell is going on? I can't for the life of me work out what would cause this.

The laptop is no longer under warrenty so I'm not sure if they will help, I also get the sneaking suspision that all they will do is tell me that I need to replace the hard drive. But I suppose it couldn't hurt to try..