An odd story and now I can't get anything to display on the monitor

A family member of a friend of mine recently had their motherboard go out. Despite his lack of knowledge about computers, he took his entire system apart and tried to put in the new motherboard himself. Needless to say, he couldn't even get it mounted. So I told my friend to have him send it to me for reassembly. When I got it, everything was loose in the case and the video card was wrapped in a plastic walmart bag...sigh. His system is a pre-built pc like you get from Cyberpower, etc.

So, I inspected everything and put it all back together. When I fired it up, everything powered up, all of the fans came on, the motherboard light came on and the GPU fan is going. I just don't get any signal to my monitor, no bios bootup display or anything. I checked over everything to make sure it was all properly installed and nothing could be shorting the motherboard and everything seems fine. He broke one of his hard drives while packing it and I don't know if it was the one with the OS on it or not but even with no OS on the working drive, I should at least see the bios screen. Also, he only left 3 motherboard screws in the box for me so the MB is only mounted with 3 screws. It feels firmly mounted though. Lastly, he lost the internal speaker, so I can't hear if it is posting or not.

Any ideas as to what may be wrong? At this point I am suspecting that the GPU may have gotten fried from the static of the plastic bag.

System specs:
CPU: AMD FX-6300 with stock cooler (I ended up replacing the CPU (he bent pins on his old one)
MB: ASUS M5A78L-M/USB3 AM3+
GPU: EVGA 550ti
PSU: no name 400W
Hard Drive: 500GB Seagate Barracuda
He broke one of his hard drives while packing it and I don't know if it was the one with the OS on it or not.
 


I'll try the first two things you suggested. I tried the onboard video last night and got the same result, no signal to the monitor. My testing monitor only has a vga input so I am using a dvi to vga adapter. Not sure that would affect it though.
 
Update: So after trying everything I could think of to get the pc to boot, I replaced the old case and the new ASUS motherboard to eliminate those as problem spots. Unfortunately, it still does the same thing, everything powers on, but it does not post, doesn't give any beeps through the internal speaker and sends no signal to the monitor.

An odd thing is that I can turn the PC on using the power button on the front of the case, but I can't hold it in and have it turn back off. My only way of turning it off is to flip the power switch on the power supply. Could that mean something?

At this point the only components that have not been replaced are the power supply, hard drive and graphics card. If the graphics card was fried (a very real possibility) could it cause this kind of problem?

Here is the case and motherboard that are now in this build:
Case
Motherboard
 
ANOTHER UPDATE:
SO i unplugged everything, replugged it all in, then I noticed that my friend's family member (who owns this PC) had switched the power supply power switch to 230V. I switched it back to 115V and now I can turn it off by holding the power button on and best of all...when I turn it on, the internal speaker gives me a single beep that is about .5 seconds long!

But...I still am getting no signal to the monitor at all. Also, after giving me the .5 second beep when it first starts up, about every 30 seconds or so it gives me the same beep again. Any clue as to what that means? Is it just doing it because it is waiting for me to navigate into the bios menus?
 
Final update:
It lives!!! I monkeyed around with it some more, then completely unplugged the graphics card and tried the onboard video (which i didn't realize it had until just now) and I have a display! Even put the windows 7 disc in and it started loading up the installer. So after all that, the initial problem my friend's family member had were that the motherboard and video card were both fried.