When I click the power button on my harddrive the power doesn turn on. I removed all of the plugs and nothing happened

If your not getting any power use a multimeter on the hard drive power cord,, probe orientation doesn't really matter you just get a negative reading if it's reversed. One probe down the middle one of the metal on outside of power adapter. Can't get a probe down middle just stick a paper clip and just probe to that. If it is getting voltage then the dc jack inside the hard drive enclosure could have broken loose take something pointy and gently push the jack on the hard drive if it wiggles it's broken and needs to be re soldered. Comment back for more assistance if needed, General solutions below
Check the following

• With the drive plugged in on powered on place your hand on it should be able to feel it vibrating (if no its not getting power or dead)
• If power and vibrating put your ear to the drive (repeating and squealing are bad, crunching sound is generally ok)
• With the drive plugged in and it sounds ok and it's vibrating[platters are spinning] right click on "Computer"/"My Computer" select manage > Disk Management, locate your drive if it is listed try to initialize it

1. Right Click drive, properties, hardware tab, select drive, properties, volume tab and click populate