Try a hard reset. Make sure all the cables are plugged in the drive. Simply shut down the computer then unplug from the wall. Push in the power button until it flashes then plug it back in again and restart the computer this will reset everything to default startup. Also if this does not work then go into the BIOS and set computer to default settings that are failsafe. If this does not work click on F8 go into the safe mode and see if the hard drive is there.

If not go and turn off the machine then open the box and pull the drives cable and power supply restart the machine then shut it down again and plug the drive back in with the computer off and hook the power supply cable back up. Plug the computer back in and restart if you get a blue screen at the start your drive is most likely faulty and you will need to do another re-install. If that does not work then the drive is faulty and needs to be replaced. I hope this assisted you, thanks for using FixYa for your questions. Be sure to comment on my fix if you fell like it. John