No drives were found...there are no fixed drives to show

I tried everything i could,nothing worked.
i think that my hdd is dead
few days ago it was working perfectly
idk what happen
please help me

From Troubleshooting Windows 7 Failure to Start:

Boot into BIOS setup to see if you can find any listing showing the HD is still alive. If so then run the maker's HD Diagnostic extended CD scan, following by a Disk Check from the installation DVD or Repair CD's Command Line.

If no sign of HD listed anywhere in BIOS - usually by a serial number you can google to find its make/model - then try reseating it or changing its cable to get it to register.

If HD cannot be made to register in BIOS, then replace it to do a Clean Reinstall Windows 7.

The best upgrade one can have is to buy an SSD, lightning fast, faster than buying a new high-end PC without one. Best deals of the day - Page 34 - Windows 7 Help Forums

i tried everything,also opened hdd to see it there was everything all right,but when i pluged it it started working and in few second it stopped.
i think that it's dead and i'm going to change logic board