|Again this is a hard ware issue. You may want to post this in the hardware forum.|
As for you problem, it sounds like either your hard drive has died, your hard drive controller has failed or your BIOS is not configured properly. Go into your BIOS and make sure the Hard Drive is set to automatic.
If could be just simply bad sectors on your drive. If this is the case then get an external CD-ROM drive (because most Netbooks don't have an internal one but if yours does then use it) and boot off of a Windows disk into the recovery console and run a CHKDSK.
If this does not work then you will have to take it into a shop to get the impervious two possibilities checked out. I hope you backup your files.