First, I would check to make sure that the hard drive is seated properly. I'm not sure how you BIOS structure looks but is it being listed? If you go to your boot menu, does it show up? Have you tried pulling the lid off of the hard drive cage and checked to see if the drive is vibrating? Also, do you happen to have a spare laptop hard drive that you could test?
My first assumption would be that the drive is corrupted. If this is the case, you can scavenge any data you need using a Live CD.
Also regarding the laptop itself, perhaps it's time for an upgrade. There's only so much you can do with a 9 year old laptop, and today's hardware has surpassed what was available back then by miles. Purchasing an SSD may have somewhat of a noticeable effect. What you should ask yourself is: Are you happy with it's performance? If no, then it's time to put it up on Craigslist or even better, sell it to a recycling center.
Hope this helps!