Power Mac g4 Won't start

Hi,
I am new to this forum and I have a rather major problem.
I have a Powermac G4 MDD and my friend recently gave me his mdd for parts. Wondering what I could do with it, I saw a post on xlr8yourmac.com http://xlr8yourmac.com/systems/mdd_c....html#storytop
With it i hoped to cool down my PS so and CPU to quiet down the fan noise. Well I took my friends case, which seems to be an older model case than mine, cut a hole in it, and took everything from my computer and put it into his case. Now, when i try to turn on the computer the power button's light goes on, and nothing else happens. What did I do wrong? How do I fix this without bringing a mac with a big hole in it all the way to the apple store. (it would be kind of embarrassing to explain that). Any help or input would be VERY appreciated