Pc Random Crash

[Johndays]

Hi

my pc is getting random crashes, it just freezes randomnly and I have to reset it in order to use it again, the screen just stays the same as the last second working, but I cant move the mouse, type on the keyboard, anything. It doesnt matter if Im gaming or just browsing, it just crashes. Sometimes when it crashes, the speakers produce a strange sound that it very disturbing.

My specs are:

Intel core i5 2400 sandy bridge
2x2gb supertalent memory at 1066 MHz
1tb hdd seagate
radeon 6870 1gb sapphire
xfx powersupply 550 watts core edition
gigabyte board GA-Z68A-D3H-B3

I tried changing the power supply, I had another power supply but changed it for this xfx core edition, same problem. Tried with windows memory diagnostics (advanced test) and it doesnt detects errors. Even took the pc to a repair center and they told me that the pc doesnt have any problem. The problem is that it can crash 1 hour after starting as it can crash 40 hours later. its at random times.

Please help me!

Thanks in advance

 

[RandomTox]

Could be a number of things that causes that problem. Go get memtest86 burn it to cd, boot your PC from it and let it run overnight (2 hours is never enough to be sure). If an error is found in your memory it will be shown in a red bar from left to right.
Open command prompt, run checkdisk by typing the following: chkdsk c: /r/f (where c: is your c drive). Do this for all drives you have.
If given more then 0kb in bad blocks/sectors, your hard disk is dying.

 

[Johndays]

Could be a number of things that causes that problem. Go get memtest86 burn it to cd, boot your PC from it and let it run overnight (2 hours is never enough to be sure). If an error is found in your memory it will be shown in a red bar from left to right.
Open command prompt, run checkdisk by typing the following: chkdsk c: /r/f (where c: is your c drive). Do this for all drives you have.
If given more then 0kb in bad blocks/sectors, your hard disk is dying.

Hi, It didnt work, I ran the memtest86 for 7 hours and didnt detect anything. Also ran checkdisk on cmd and there is no error.

Didnt told you that I also do a low level format for the hard drive and installed windows 7 ultimate 64 bits again, same problem.

Please help

 

[RandomTox]

Are you running stock settings or overclocked?
Check In the BIOS if the memory settings are correct. Most memory have stickers on them with their settings. Be sure the voltage is correct too.
Do the same for the CPU. How is it with the temperature of the CPU and GPU?
Do some stress test on your GPU with these tools:

http://www.ozone3d.net/benchmarks/fur/
http://www.guru3d.com/files_details/3dmark_11_basic_edition_download.html

 

[Johndays]

Are you running stock settings or overclocked?
Check In the BIOS if the memory settings are correct. Most memory have stickers on them with their settings. Be sure the voltage is correct too.
Do the same for the CPU. How is it with the temperature of the CPU and GPU?
Do some stress test on your GPU with these tools:

http://www.ozone3d.net/benchmarks/fur/
http://www.guru3d.com/files_details/3dmark_11_basic_edition_download.html

Im using stock cpu and gpu settings, no overclocking. I changed the memory timings and voltage according to the information on the manufacturer page, same problem. Tomorrow I will borrow a pair of kingston ram sticks to see if the memory is causing the problem, even though they passed the memory diagnostic test 9 times (7 hours test). The temperatures on the cpu and gpu are very very stable, the case runs very cool (4 fan and a lot of airflow due to its size). It doesnt matter if the pc is idle or gaming, it freezes at random times.

 

[RandomTox]

Is the power that comes from the plug in the wall constant?

 

[Johndays]

Is the power that comes from the plug in the wall constant?

The pc is connected to an apc battery with battery backup and surge protection, the power that comes from the plug in the wall must be constant, if it is not constant in a moment then the battery makes a sound signal indicating that battery backup is enabled, this has not happened to me yet so I think that the power must be constant. I dont know what to do, will try to buy a pair of kingston memory sticks to see if it solves the problem, everyone who have this type of crashes solved it by changing the memory sticks. If you have any other recommendation please let me know, thanks!

 

[Johndays]

Please help, now im getting a lot of blue screens of death, installed a pair of new kingston hyper x 1600 mhz to see if memory was causing the problem, it keeps freezing and getting bsod, help!