If you do have important files, that you want to save, then there are two options I can think of:
- take out the hard drive, and connect it to another computer, for example via USB (with an external enclosure). If the hardware is OK, then you should be able to copy the files.
- create a bootable USB pendrive with an operating system on it, boot on it, and see if you can see the content of your hard drive from there. For example, you can create an Ubuntu system on a pendrive (>=1GB).