Hey guys  
 
So about 6 months ago i built my first PC. Today i think something is broken with it or failing.  
 
My issue 
Today i loaded up BF3. i played for about 2 hours with no problems. after that i hit the end of the round screen and my PC hard locked. Thinking it was a one time deal i restarted and continued as normal. however this time while in BF3 when i whet to my kit customization screen (in game) i had the same hard lock. i rest again, and when i reached the Windows log in screen booth my keyboard and mouse were dead, no lights on both items. unplugging them and plugging them back in to different ports (USB) yielded no results. i then restarted again and my mouse and keyboard worked fine. i let my PC idle for about an hour and came back and it was working, it navigated windows and the web fine logged back into BF3 played a entire match with no problem. got to the end of round screen and hard lock. restarted again, thinking it was my GPU i loaded up the witcher 2 let it idel for about 10 mins and when i returned the computer had hard locked again. updated my video drivers to NVIDIA's latest beta drivers and now the system wont show the ASUS logo or the windows is starting up screen. its just black for about a min until im presented with the windows log in screen. tried poking around in the NVIDIA control panel and my mouse and keyboard died again. What the hell is going on?  
 
My spects 
 
Windows 7- 64 bit 
Intel i7-2600k 
GTX 560 ti (MSI Twin Forzer II) 
16 gigs of RAM 
Mother Board -asus p8z68-v pro 
 
This is a custom built PC

If you're not getting Nvidia driver crashes then it'll be either your RAM or your Hard Drive.

Do you have anything overclocked? If so, revert everything back to stock settings.

Do you get any BSoDs at all?

Also, drivers should have no effect over anything outside the operating system, so whatever happened with the logos not showing before Windows loading, it shouldn't have to do with it. But perhaps it can help in determining the issue. Start by testing the easiest components then go from there.

Run Memtest a couple of hours and see if you get any errors. If you get nothing, run tests in Prime. Start with Small FFTs, then do a Blend test and keep monitoring temps while doing it. If you still get nothing, then run a GPU stress test (you can use MSI Kombustor). And if that still doesn't get you anywhere, you can download a tool from your HDD manufacturer to check the drive for errors.

@Jackel2072 said:

@SeriouslyNow: it has been starting up slower over the last month or 2. noting long mind you. its just been taking an extra minute or so to finish loading all the desktop applications.

Simple tests:-

• Get malwarebytes antimalware. Update it and do a full scan.
• Boot and run with only one stick of RAM. Run Memtest86. Swap them around, repeat the process until you find the culprit.
• Use a completely different drive. Run as normal, see if the system locks up in the same way.

Hopefully you don't find out what is failing by returning to find magic smoke coming from your pc.

In all seriousness though, are you running everything at stock settings?

most likly a HDD or ram problem but it could also be a motherbord or software issue.

if software just try reformatting everything. and reinstalling everything from scratch. if you still have the problem buy/borrow a hdd and replace the master drive with that and unplug all other hdd if that not the problem then atleast you got a new hdd. for ram same thing or Run Memtest86. Swap them around motherbord problems, your screwed.

make sure the rig is clean and not overheating and dont overclock anything.

Thank You GB community for coming to my aid. As of this moment i am running my PC on one stick on ram and i think that is where the problem lies. everything is ok at the moment. system booted up normally, hopped into a round of BF3 and no issues so far. im just going to test each stick individually and see what happens. Also yes i am running everything at stock. 

Windows Key > "View Reliability History"

Should bring up a window with a graph looking thing. Look for the little red X's, they should tell you what is causing the computer to crash.

Memory as you seem to have found may be the issue but can't hurt to check reliability history. If RAM is the issue it should be cheap enough to replace.

question. so i am running 2 diffrent types of RAM 
 
The first pare i bought  failed, CORSAIR sent me a replacement unit which was this one. could this be causing the error?  i have both of these in my system at the same time.
 
1.   http://www.newegg.com/Product/Product.aspx?Item=N82E16820145345 
 
2.  http://www.newegg.com/Product/Product.aspx?Item=N82E16820233246

Check your temps with your monitoring program of choice. I had BF3 hard-lock on me a couple of times in a row a few months ago. Turns out the fans on one of my gfx cards were dead.

did you run memtest yet?

put all the sticks back in the computer like you had em while they crashed, see if you get any errors.

if you do, run every stick by itself ( make sure you place it in the right slot for single ram use )

hopefully you'll find a faulty stick.

otherwise it could be caused by the differing timings on the different kits you have ( the black ones are a tad slower )

if the motherboard forces them to run at the same pace as the faster kit, it could make em a bit unstable.

Have you checked out your CPU's and GPU's temperatures when you run games? Also do you have a stock Intel cpu cooler or a aftermarket one? If latter and you put too much or too little thermal grease, your computers hard locks might be caused by heat problems.

Stop and run some stress test as they will help force the error to pop up and help diagnos the problem. So run memtest scan your hdd for bad sectors and stress your gpu and CPU for heat problem.

It could be multiple things. Heat damage, broken fans, loose screws causing shorts, etc. You said you built it yourself so crack it open and do a thorough hardware inspection.