You should do/check the followed things:
[li]Check the BIOS if the drive is detected, depending on your PC/board manufacturer the connected drive should be displayed during init of your PC.
[li]Check the cables (SATA and power) if they are really compete plugged, you can unplug and plug the cable again to be sure.
[li]Change your SATA cable to be sure the cable is ok, you can also use an other power connector if you still have an unused SATA power connector
[li]Use an other SATA port in case the SATA port is not working correctly
[li]Check your drive in an other PC to be sure the drive is not broken