I recently wanted to change out hard drives for more space on my dad's desktop computer. The power, cpu, cd rom drive and floppy drive are working. When I plug just the power cable into the hard drive (without the IDE cable) I can feel and hear it come on. When I hook up the hd to the IDE cable it dosent power up. I have hooked everything back up like I found it. Need some help to get this computer up and running!