Windows doesn't load. Can't see motherboard(Gigabyte) logo, can't see windows loading screen, Nothing. Just the blank screen.

Did you buy the system already built or did you put it together yourself? If you built it yourself, did you use your old windows on your hard drive or did you clean out your hard drive and install windows brand new with the new motherboard? It sounds like it's not getting signal to the monitor, are you using the igpu on the 4770 or a stand alone graphics card? Have you tried booting with 1 stick of ram?

You can try turning off the pc, removing the cmos battery and wait a couple minutes, put the cmos battery back in and turn the pc back on. This will set the bios back to factory defaults in case some settings got changed. If you can get the machine to boot (I know you can't see anything at the moment), maybe you can check to see if you have the right bios (version f5) for that cpu.

When you said you tried another cpu and tested it and it worked, did you remove your cpu from the motherboard and use a different cpu chip? If so, which processor? Or do you mean you connected your monitor to another pc tower all together and the monitor worked then?

Resetting the bios to factory defaults should have fixed any display output settings that may have gotten messed up. Since you don't have a graphics card I'm assuming your monitor cable plugs into a port on the motherboard? A couple more things I would try, one is turning the pc off and making sure that all the power cables are firmly plugged in on the motherboard. The 4/8 pin cpu power cable (usually near the cpu socket either below it or most likely above along the top of the motherboard) and the 20+4 pin mainboard power cable usually along the right edge of the motherboard. Remove the stick of ram and try installing it again to make sure it's firmly locked into the ram slot.

If that doesn't work and if you still have your old pc and can connect it to the internet, try downloading a linux livecd and install it to a thumb drive. Then insert the thumb drive into the new pc's usb port and try to power it on and see if it will do anything. It's just a last ditch effort since you should be able to get some sort of display output showing the bios information before windows even loads, so even if it were somehow a windows corruption issue it shouldn't be affecting your pc to the point it has no display at all.

If you have another stick of ddr3 ram, you can try installing it into your new machine in place of the current ram that's in it to try and rule out a bad ram stick. Beyond that, without another known good cpu chip to install in your new machine there's no way to tell for certain. It's always possible that you have a bad cpu chip but it's equally possible (and maybe more likely) that the motherboard is faulty.

With everything in warranty, I would take it back to the place I bought the pc and have them work to fix it. They should replace either motherboard or cpu (or both) depending which is faulty until it's working properly. If you don't have a separate graphics card then you're using the integrated graphics which is built into the cpu. The motherboard then has to transfer the video signal to the plug on the back of the pc where your monitor attaches so either one being bad can result in no video output.

Hook up your SSD/HDD to a computer and browse its files, you want to go to (Random letter):Windows\ or (Random letter):Windows\System32 and upload a MEMORY.DMP file to a file hostiing service since that memory dump will help me out with the issue you have.