Hi. Is that HDD the only hard drive you have installed on your PC? If so, I remind you that the system partition is on that disk. How far can you get when booting up? Do you get the Windows logo? Have you tried a different power connector? I don't think the PSU is the problem here, since you are getting good power for the rest of the components which by the way, they use the same voltages. Have you ran any HDD diagnostic utilites yet? If not, download SpeedFan for free at:
Download SpeedFan - Access temperature sensor in your computer
and run it. Click on the "S.M.A.R.T." tab, then select your HDD from the "Hard Disk" drop-down menu and click on the "Perform an in-depth online analysis on this hard drive" button. It will tell you the health of that hard drive. I believe it's defective or dying. Also, if it's the only hard drive on your system, is it sharing the IDE cable with another ATAPI drive like a CD-ROM? That,pretty much always, causes conflicts between the drives; they need to be connected to the Mobo on different IDE controllers. Post back with more info and answers,please. Good luck!