First Build: System Posted, Now It Won't

Abstract:
I got my computer to post yesterday, but now I get no display today.

Summary:
I completed my first build with the help of this site and finally got it to post to the screen that says "insert operating system and press any key." I didn't have an OS yet so I simply turned it off, TOUCHED NOTHING INSIDE, and went to bed. The next day I got Windows 7 and booted my system so I could install it, everything turned on except no display this time.

Last night I got it to display the boot screen beautifully, and now I get no signal.

I have a speaker plugged in and hear no beeps upon startup. Everything comes on, fans, processor fan, graphics card fan, DVD drive opens, power button lights up and face plate LED lights up, keyboard/mouse come on. Everything runs continuously but I still get no display. All I hear when the system boots is the fans/HDD start spinning.

Specs:
CPU: Intel i5-3570k (Stock CPU fan)
MOBO: MSI Z77A-G43
RAM: 8GB Patriot Black Viper 3 DDR3, 1600MHz up to 2133MHz at 1.5 volts (Model: PV38G160C9K)
VIDEO: EVGA GeForce GTX560 Ti
PSU: Antec Earthwatts EA-650 watt
HDD: Western Digital 1TB Caviar Black SATA Internal Hard Drive
CASE: MSI Nighthawk Mid ATX

*I worked with an employee at Fry's to make sure everything was compatible.

Steps I've taken:
1. Consulted motherboard's owners manual to ensure everything is correctly positioned and securely seated. (including 4 pin CPU pwr, mobo pwr, video card+ PCI-E pwr, fans pwr, HDD/DVDD+pwr/sata, front panel USB and pwr button)

2. Checked standoffs, no imperfections

3. Booted with 1 RAM stick (tried every different slot) pressed RAM with both hands firmly until it locked itself

4. Checked for loose parts/screws

5. Installed speaker into motherboard slot labeled: "(speaker+)(buzz+)(buzz-)(speaker-)"

6. Reset CMOS (removed battery for more than 3 mins)

7. Tried plugging VGA then HDMI into onboard ports then video card ports

8. Double checked everything seated securely

9. Got extremely frustrated

10. Resisted the urge to smash

Conclusion:
I figure if I got it to post, then everything was connected right. (Obviously not I guess)
Can anyone please help me figure out how I can zero in on the problem? At what point do I decide its damaged parts? I'd really appreciate any insight. Thanks guys.