CPU usage at or near 0%, freezing, very slow boot up

[GovernorG]

So lately on my 1 1/2 month old built PC my CPU usage is at or near 0%. The boot up time takes 5 to 7 minutes and when I need to have administrator power to select yes or no (which I do) for applications (user account control) it freezes my screen and the gray shade stays and the audio keeps working.

MY PC:
i5 3570k @ 3.4
WD Blue 500GB
ASUS p8z77 v pro
GTX 560 ti
8GB corsair vengeance @ 1866

All of these are new parts. I haven't been able to play most of my games or install updates. When the freezing occurs I press CTRL ALT DEL and the gray back light shade goes away and it doesn't process my answer as yes and slows my PC down to the point of frustration. I have been keeping up on the latest drivers and haven't been installing suspicious or harmful software. Even though I have admin power on my PC it still freezes and cannot figure out what is happening. I have bursts of normal power usages here and there but then it goes back to the slow, freezing, old problems again.I have seen some similar problems to mine on other sources but i'm not sure if I have the same solution. Help?

 

[TenPc]

8GB corsair vengeance @ 1866, check the manufacturer website for instructions to using the 1866 ram, usually, you need to use one stick in A channel and one stick in B channel.

 

[GKG]

I got some similar issues, CPU goes 0%, run slow, crashes then do not power on for a long period, i guess MB got some bad CAPS or transistors...