Mid 2007 Aluminum 24' IMAC When powered on LED diagnosis lights are all lit green but all I have is a white screen and nothing else?

I tried resetting the PRAM and something else I can't think of that started with an S. I don't have another Mac here. Also, when I turn on the IMAC I can't get anything to happen besides the gray / white screen. The optical drive won't eject and I'm currently waiting on a replacement to get here. I just don't want to order a new screen and LVS cable to find out it was just the hard drive. I read through quite a few forums where several people said this problem can happen from having a bad optical drive (which I have) and or from having a bad hard drive. A few people who claimed to be techs said the same problem with the white / grey screen is 90% a hard drive issue with this model. I just thought maybe someone who's worked on a few of them would have some experience with this. I will try and go through all those steps in that link suggested though so thanks. This is 100% not going to an Apple repair center. The prices they charge to repair something out of warranty are beyond ridiculous. I just formatted a brand new 480GB solid state drive in a 3.5" hard drive caddy. When I put a disc in the optical drive it will spin and work, it just won't eject so I'm thinking after putting the new hard drive in I'll slip the disc in and maybe something good will happen. It just ***** taking everything apart including removing all those screws and stuff just to diagnose the problem.

Well I replaced the hard drive and superdrive praying it was the hard drive. Nope, still the white screen. I ordered a new LED screen with a working inverter for $70 that were rated an A-. Can be the only thing left, I've replaced everthing else pretty much except the power supply! LOL Just ***** how it could just be the inverter and the only way to find out is to order the parts and plug them in to find out. I have someone bringing me there MacBook Pro tomorrow, actually the person who's Imac this is. He had me order a firewire cable so he could hook it up to the IMAC so I'm going to see if I get any kind of image from the IMac onto the MacBook and vice versa. Apple has to make everything so complicated....