Sounds like you have a bad hard drive there. If the machine still actually boots copy everything off of it you can as soon as possible to an external drive. If the failing drive is under warranty send it back to the manufacture.
Find a friend with a computer, install your HDD into it. Download TestDisk (it is free), read the wiki. Start TestDisk to begin recovering recoverable folders and files. If the HDD is phsically damaged, you will not get all your files, and you'll have to copy them to a target drive one by one. It does work, so if you have important files, it may be worth your time and effort.
It works, I've been recovering files from a failed HDD for several days now.