Hard drive resurrection
First, you can transfer all the contents of the existing hard drive to a new one. Or, well, you could, save apparently that existing is now not working. If that on it was really critical, there are outfits that at a cost may be able to retrieve this data. Otherwise, this is academic.
As to whether a 2008 MBP is worth resurrecting is more a personal matter. Apple will likely tell you it is not, or that your computer is basically obsolete. New Macbook Pros will run circles around it in performance. But as mentioned by others, replacing but the hard drive is a simple and fairly inexpensive process. So, it may be worth it to you, if in no more than having this for now and then later as a backup.
Save the retinas, with the possibility of several Version A glitches, you'll be fine with a new MBP. Anything mid-2012 or newer should suite you fine; and do not overlook the option of buying a refurbished unit from Apple (being a good value, and reliable).
If deciding on a new hard drive, that similar to that existing would be the least costly. But as good SSDs of 256GB can be had for less than $200, you might seriously consider that option. If so, you'll not only resurrect your MBP but see it more sprightly than ever before: it would prove more than necessary repair, and a big improvement.
Enough so you might contemplate holding on to that believed 2008 for some time to come. Although do consider what a new model could do for you.
