I put together a new computer a few months ago with the following components
ASUS P8Z68-V Pro
Corsair Vengeance 8 GB Memory - DIMM 240-pin - 1600 MHz
700 Watt Coolmaster PSU
CM storm scout case
Standard 500gb HDD
Samsung DVD Drive
It all went together fine and ran well for a month. Then I booted up the computer one day I was given a green screen before the bios. After 5 seconds the computer went to a black screen and locked its self up. Then, when I tried to boot up I was given an error by windows reading something like 'admin logon failed' the message would keep popping up and would not let me into Windows.
So I decided to reinstall Windows 7 from fresh. Now the computer keeps failing Windows updates over and over. It will get stuck half way through an update and I will have to cancel the update or force shut-down the computer(if it's installing while shutting down)
I am also being given blue-screens during the updates a lot one of them were 0x0000019 and the other was 0x0000000 < - this one kept happening over and over when I tried to run an particular security update
So the next step I took was installing Windows 7 on another HDD and use the intergrated graphics(removed the graphcic card entirely ) on the motherboard. I still got the same blue-screens and Windows failing/freezing during updates.
Where do I start with this problem it's driving me mad.
Couple of things I would check would be to press F8 just after the BIOS screen disappears and before Windows boots. This should bring up the Windows boot screen where you can select whether to boot normal, safe mode, etc... One of the choices should be a memory test as I recall. I am pretty sure this is right although I have never had to use it myself. Alternately you could get some bootable CD with memtest on it.
The other thing I would check is the ASUS support site to see if there are BIOS updates that address such issues. I do not own that motherboard, but I have heard of various issues. And of course you can Google "ASUS P8Z68-V Pro problems".