Visnic PC games, jamming sound

Please read to the end, the text came out long, sorry

Bought the computer about 5 months ago

C2D E8400
4 GB OCZ Reaper (4 bar gig)
Microstar 8800 GTS 512 mb
Giga Byte GA-P35-DS3
Thermaltake TR2 550W
WDC WD1600YS-01SHB1
WDC WD5000AAKS-00YGA0
Antec Nine hundred

Started to put Windows, put it with constant blue screens where the 3rd attempt with a lot of restarts and blue screens were supplied, but terribly buggy
Figured out that everything works perfectly if is at 1 - 3 bar.
ie one of the slats didn't want to be paired with any of the other three, but one by itself worked

In General, the memory I replaced the 4 gb OCZ Gold XTC OCZ2G8002G (2 x 2 gig)

The system began to work steadily, but began the problem with which I'm involved already 4 months
Started to hang some games (Gothic 3, Titan Quest, Two worlds, Crysis, Call of Duty)
The picture freezes and the sound begins to jam, well, as fashionable songs do
Millisecond of sound repeats itself like rrrrrrrrrr
Sometimes the sound becomes normal again (picture hanging) and again begins to crack
Helps only reset button
Some games you can play until blue in the face, nothing will hang
In the BIOS setting performance Enhance Turbo is supplied as Standard
Everything stopped! But not for long, started to hang again but less frequently

Around the same time, somewhere a month later the cooler is in games have stopped working in full
Began to accelerate only slightly (the noise increases only slightly)
And initially after buying it was overclocked for about 2 minutes in all games to the max (very noisy)

I started great testing...
Updated direkth, changed performance Enhance memory strip places changed, the voltage on the 1.8 set
Chased the hairy cube ATI, озон3Д hairy bagel, 3D mark 2006, Hot CPU tester pro, VMT, prime95, test disk - all tests pass without errors except S&M

In S&M left in the options, only 1 and 3 checkbox in the test memory (the rightmost)
After the end of the 3rd test at 100% the program cresida and writes:
>
Process number: 0
Test number: Memory (1)
Exception code: C0000005h
Exception addr: 00AF0006h
01 00 00 00 00 00 00 00 00 00

This is the only program issuing a single mistake

Then there is another issue in the last month
A week or a little more ago the computer rebooted itself ( not seen on this do not know sudden restart or shutdown)
And hung on a black screen which appears immediately after switching on there where the percent is written, memory, etc.
And hanging on this
Helps only reset button

In the end, I changed the memory again, now I have a CSX, also 2 for 2 gig
The computer worked for 6 days and not hung, but hung it so only 2 times

After changing the memory played Call of duty 4 online
The game freezes in an hour, then again in an hour
The most interesting thing that Wisla it is when the round ends and the scoreboard appears
Put performance Enhance Turbo is Standard (threw off the BIOS battery after changing memory)
The game freezes after 2 hours but when I switched to the browser and again with him in the game Alt-tab a
After playing 4 hours, switching, nothing hanging
Recently Nacala hang as well but with the screen flicker with bands such as if the camera shoot the monitor

In General, the patterns no
Tell me something please, what could be the cause of my troubles?