G5 becoming a money pit

My iMac G5 refused to start recently after Start Up I got an alternating finder icon and question mark. After some research I discovered my hard drive wasn't showing up. And using a start up CD I can see there is no hard drive detected.

So i went and bought a new one installed it easily.

Go to boot up same problem hard drive not reconized.

After researching I cant find anything close online and after looking over the previous threads I had to ask If any one can offer any advice as to my next course of action. I saw a guy selling parts online my next guess was to try the motherboard.

Thank you for reading and in advance for any thoughts or ideas.