If the present hard drive can not be made to work, a new drive can be obtained for around a hundred dollars. It is a fairly easy replacement. When your computer was new, hopefully it came with a CD that you could use to rebuild or reinstall your operating system. You will need this CD to install the operating system on the new hard drive.
Something I read a while back.
It actually worked for me when a 120GB hard drive on my desktop started to act funky.
Take the hard drive and put it in a plastic bag.
Then, put it in your freezer!
After a couple hours, take it out and plug it back in.
You now have about 15 minutes of successful run time before it starts acting up again, or maybe just fails outright.
I was able to rescue everything I didn’t have backups of, so worked for me!