If you have a windows 7 disk, get into bios, and turn the boot device to cd/dvdrom and put disk in. It will spinup and ask what do you wish to do. Select repair. Its sounds like your hard drive is bad, and chkdsk from cd will check and repair for you if it is a disk error.
If you have never logged into bios, then you are better to take it to a repair shop, and it is not a 1 2 3 fix. You must be able to logically think about what task you are trying to perform, so if you have never logged into bios, take it to get repaired.