If you are using a new HD, tried two different cables, in two different SATA slots (OK, maybe you should try a different power connector too) . . . the problem is most likely somewhere on the mobo.
Try resetting the CMOS (pull the plug on the psu, remove the battery on the mobo, press the tower's power on button a few times, then go grab a cup of coffee, er wait 10 minutes. Then put the battery back in.)
Boot up the PC and get into BIOS Setup. Normally this requires hitting a key (often DEL, maybe an Fn key) repeatedly almost immediately after powering up).
In BIOS, find the way to "Load Defaults". Then find the page that shows what devices are attached to the IDE channels (might be called Standard CMOS Features) and see if it found your disk drive.
If yes, edit other BIOS values as necessary, save, and exit.
If no, the mobo is at most likely at fault, though there may be a tiny chance its the psu not powering the HD correctly.