In my experience, you are probably right. It is probably you hard drive malfunctioning.
It depends how far gone your drive is, in regards to how easy it will be to recover the data.
In many cases, removing the hard drive and connecting to another computer as an external drive will allow access to the drive.
You can get an USB to IDE/SATA cable for around $20 from Newegg. They are easy to use, and, if the drive is still somewhat functional, it will be like taking information off a thumb drive.
If the drive is too far gone, you may need to pay a professional, but normally the cables do the trick.
You will probably need a new hard drive & operating system, if you want to continue using the computer.