Hard drive compatability with power supply?

Greetings, I have recently recieved a computer off of my school and since it has all the school software on it, it is completely unusable for home use. I'm looking to buy a hard drive off of Amazon but i'm not sure if its compatible with my power supply and motherboard(?)

here's the Hard drive i'm looking at:
http://www.amazon.com/Western-Digital-Caviar-Cache-Desk...

and heres a picture of all the cords that went into the original hard drive from the school:


If any additional information is required, powers supply model etc, I may need guidence on how to obtain it since i'm not that "technologicaly savvy" if you will. Sorry if this is in the wrong section as this is my first post on Toms Hardware...