Before installing the OS update the BIOS first! Use the ASUS EZ Flash 2 method, you'll need a Flash Drive and IMO get at least a 4GB or better 8GB. There are so many things that can screwed-up building unless you've done it a few times. The Z68 in particular make sure the SATA -> AHCI and below:
BIOS for d-Mode
Initiate Graphic Adapter -> PCIE/PCI ; otherwise BSOD
iGPU Memory 64MB ; or more
iGPU Multi-Monitor -> Enabled ; required
If I were a betting man, I probably could have gotten the P8P67-M PRO rig to work.
Also, before installing Windows even if the MOBO ships with the latest BIOS, assume it's corrupted and Clear CMOS right after pulling it out of the box; see -
http://www.youtube.com/watch?v=rdHH9KrceR0
If you have an SSD then make sure it has the latest Firmware and ditto with the HDD(s). Never use the drivers that come with the MOBO - 9/10 their old, download and install only the drivers from ASUS's website. Aftermarket HSF, READ THE MANUAL TWICE, if the HSF has a metal back plate then regardless of what the manual says:
Screw -> Metal Back-plate | Plastic washer || MOBO || Plastic washer | ...
If the case doesn't have 'real' standoffs then either use two layers of electrical tape or Case | dab of silicone | Plactic washer || MOBO.
Generally, it's best to boot the MOBO outside of the case before installing it into the case. NewEgg has a 3 video Building series that I'd recommend that you watch; see ->
http://www.youtube.com/watch?v=lPIXAtNGGCw Most folks it's best to have the HSF and RAM installed then place into the case.
Also, you MUST properly clean both the CPU and HSF, wipe-off with a lint free towel then clean 2-3 times using a Q-tip and Isopropyl alcohol, get non-conductive TIM 'Thermal Paste like Arctic Cooling MX-4 -
http://www.newegg.com/Product/Product.aspx?Item=N82E16835186038 You CANNOT reuse thermal paste the old stuff is trash now and absolutely cannot be reused.