Breadboarding my PC, need some help

So I have been having problems getting my PC to start after it crashed during a power outage. After reading a bit and getting some advice, I decided to take out all the components and set it up piece by piece outside the case in order to find out what's not working.

So I took out the motherboard, put the CPU and fan in and put in one stick of ram. I then connected the motherboard and CPU to the power supply, turned on the power supply and started the system by touching the 2 power switch pins with a screwdriver. Some LED's on the motherboard lit up and the fan on the CPU started running.

I then plugged in my GPU and connected my power supply to it. After trying to start the system again, it would do nothing. No LED's light up and the CPU fan does not start. Now I am assuming that the problem is coming from my GPU but I am still unsure of how.

Is it possible for a faulty GPU to make it impossible for power to reach the motherboard and CPU? Is a working GPU necessary for a computer to even attempt to start up? IS it reasonable to assume that my problem is mainly my GPU?

Also does the fact that the CPU fan starts up and the motherboard lights up mean that my CPU, power supply and motherboard are in working order and the problem lies elsewhere? Or can the problem still be the motherboard even though it is stable when it and the CPU are the only things plugged in?

Any beeps? Do you have a case or motherboard speaker?
http://www.newegg.com/Product/Prod [...] -_-Product

Can you borrow a video card and test with it or test yours on some other PC? Also the monitor on some other PC.