Hi everybody. I'm looking for support and maybe some of you may be able to help.  
 
About a week ago while playing MOHA my pc just shut down out of no where. Ever since my computer has been running very unstable and I'm having a hard time trying to diagnose the problem.  
 
Here are the symptoms:  

• cpu freezes for about 2 seconds then releases. I notice in the CPU usage gadget (vista) that when the freeze happens core 1 jumps to 85-90% usage while core 2 stays at 0-5%. Core 1 then releases and drops back down to 0-5% and I regain functionality. This happens on a constant basis and especially when a load is put on the cpu such as opening a program or on the web.  
• sometimes after boot-up my 2nd sata drive is not recognized in explore.  
• sometimes after boot-up I get a dialog box that says my soundMax driver needs to be reinstalled and I have no sound.  
• and on rare occasions after boot-up I get multiple dialog boxes from my BIOS that shows some kind of error with my CPU. I'll try to post this error next time this happens.  

Here's what I've done so far with no positive results:

• I've re-formated my primary drive and reinstalled win Vista with all updates two times.  
• I've changed out the memory modules with newly purchased ones and still have the problems above.  

I believe this is hardware related. I just don't know if it is the power supply, cpu, or mb. I'm hoping its the PSU though.  
 
Here are my specs:  
OS: Windows Vista Home Premium (32)
MB: Asus P5N32-E SLI
CPU: Intel E6850
VGA: EVGA 8800GTS 512mb
MEM: Kingston HyperX DDR2 800mhz (2x1Gb) (On ASUS AVL)
PSU: Thermaltake W0106RU Toughpower 700W
 
Let me know if you need any more info.
 
Any suggestions?  

I should also add that this current system is only 3 months old and I've never had any problems until I played MOHA (in winXP compatibility mode). I've also never updated the bios.

Get meter and measure voltages, PSU is prime suspect. Install Speedfan and monitor voltages, especially 12V for dips on Graph tab. Download and run manufacturers diagnostic on HD. Try HDTUNE to check performance of HD.
 
       Mike.

If you're running overclocked, then reset it to stock bud.

And reinstall your graphics drivers :S...

Thanks for the reply Mike.  
 
I'm running Speedfan and it's showing +12V current value at 11.84V, steady with no dips. It is below 12V so I don't know if that may be an issue? I've also checked the voltage value for Vcore1 and it's reading 1.28V with dips into 1.26V every sec. Vcore2 seems stable at 3.25V. Should Vcore1 be stable at 1.28V?
 
I've ran HDTUNE and the error test looks fine. The benchmark test results are below. It's reading slow, but that's probably due to the usage jump in core 1?  
HD Tune: WDC WD2500KS-00MJB0 Benchmark
 
Transfer Rate Minimum : 1.3 MB/sec
Transfer Rate Maximum : 62.1 MB/sec
Transfer Rate Average : 50.8 MB/sec
Access Time           : 13.6 ms
Burst Rate            : 115.7 MB/sec
CPU Usage             : 14.1%
 
I'm with you on the PSU and I think I'm going to just replace my Thermaltake with a Corsair 750W. The corsair has a single 12V rail at 60A and is proven to be pretty stable. I've notice some comments about the Thermaltake being very unreliable and even starting some fires.  
 

System isn't oc'd. I was thinking about it though, but not any more!

Try a different keyboard. No joke.  I had a similar lockup problem and a bunch of other weird things.  The keyboard had some kind of short.  I was very surprised that it could do what it did.  
 
Just try disconnecting peripherals and stuff one at a time, thats how I found that out.  Also open itunes in the background, see if the music still plays even though the computer appears to be locked up for the 2 seconds.  Or if there are still website animations going.  
 
Another thing to do is to disassemble the computer and put everything back together again.

I agree that Jons suggestions are a good starting point.
 
Are you sure you installed all the requried drivers each time you reformated?
Do you have the latest drives for you CPU, graphics card, and sound card?
 
Are there any other characteristics as to when the cpu freeze problem occurs?  For instance, does it matter how long the system has been running?  
 
Do you ever see significant usage on core 2?

1.3MB/s?is that even normal?

 
Speedfan does not always report voltages correctly.  If your cpu was at 3.25V it would of fried a long time ago.  And 1.28 is a good voltage.  1.26 is Vdroop and it is fine.  Your 12volt rail is all right unless it is dropping lower when doing something intensive.  Run the ATI tool stress test and see how much it dips.   Your hard drive appears to be fine.  The 1.3MB/sec happened because some other app accessed the HD during benching.  
 

Do you have a restore point you can return to to see if that might take care of the problem?  - maybe some software update is causing a conflict.
 
Did the cpu freezes and bootup issues seem to start at the same time - as if a single source is the problem?  Or could you have two separate problems?

it could be your HDD is playing up.i got a friend everytime he do FRAPS when it start will take a screenshot,right at that point his pc freeze for 2 sec then comes bak on fine.

 
He said he reformatted and installed vista 2 times.
 

 
I think Fraps does that to everyone.  
 

No, 1.3MB/s is not normal... sometimes when core 1 hangs it freezes the system for 10-15 sec. I think thats why that rating is showing so low.  
 
When it hangs/freezes, the website animations are stopping and iTunes freezes too. I'm going to try playing with the peripherals next.  
 
Thanks for the tips.

Bench the HD again.  See if you get the same result and make sure all programs are closed.
 
Or are you saying it hung when benching the HD at that spot?  That doesn't mean the HD is bad, because if the system hung, I can't blame the HD for not performing well when it doesn't know what to do. (Because it's not getting orders from the CPU)

Here's the bench results again (with all aps closed).  
 
HD Tune: WDC WD2500KS-00MJB0 Benchmark
 
Transfer Rate Minimum : 1.9 MB/sec
Transfer Rate Maximum : 62.1 MB/sec
Transfer Rate Average : 49.5 MB/sec
Access Time           : 21.3 ms
Burst Rate            : 112.2 MB/sec
CPU Usage             : 5.3%
 
 
Here's a screen shot. Notice the long drops that was during the freeze.  
http://www.flickr.com/photos/23189782@N08/2543210174/
 
I just tried using a different keyboard and mouse and no change.

I just ran asus PC probe and a lot of the voltage warning alarms went off. Here's the log file.  
 
===================================================
ASUS PC Probe II
 
Alert Log Report
 
Number = 26
===================================================
 
[06/01/2008 at 04:30 pm] 1.2VHT Voltage Abnormal, 0.26 V
[06/01/2008 at 04:30 pm] 1.2VHT Voltage become normal, 1.25 V
[06/01/2008 at 04:30 pm] 1.2VHT Voltage Abnormal, 0.00 V
[06/01/2008 at 04:30 pm] SB CORE Voltage Abnormal, 4.08 V
[06/01/2008 at 04:30 pm] CPU VTT Voltage Abnormal, 4.08 V
[06/01/2008 at 04:30 pm] 1.2VHT Voltage become normal, 1.25 V
[06/01/2008 at 04:30 pm] SB CORE Voltage become normal, 1.52 V
[06/01/2008 at 04:30 pm] CPU VTT Voltage become normal, 1.26 V
[06/01/2008 at 04:32 pm] 1.2VHT Voltage Abnormal, 0.00 V
[06/01/2008 at 04:32 pm] SB CORE Voltage Abnormal, 4.08 V
[06/01/2008 at 04:32 pm] CPU VTT Voltage Abnormal, 4.08 V
[06/01/2008 at 04:32 pm] DDR2 TERM Voltage Abnormal, 3.14 V
[06/01/2008 at 04:32 pm] NB CORE Voltage Abnormal, 0.00 V
[06/01/2008 at 04:32 pm] MEMORY Voltage Abnormal, 2.99 V
[06/01/2008 at 04:32 pm] 1.2VHT Voltage become normal, 1.25 V
[06/01/2008 at 04:32 pm] SB CORE Voltage become normal, 1.52 V
[06/01/2008 at 04:32 pm] CPU VTT Voltage become normal, 1.26 V
[06/01/2008 at 04:32 pm] DDR2 TERM Voltage become normal, 1.07 V
[06/01/2008 at 04:32 pm] NB CORE Voltage become normal, 1.25 V
[06/01/2008 at 04:32 pm] MEMORY Voltage become normal, 2.13 V
[06/01/2008 at 04:33 pm] CPU VTT Voltage Abnormal, 3.33 V
[06/01/2008 at 04:33 pm] CPU VTT Voltage Abnormal, 3.33 V
 
This is really starting to make me think its the psu.  

your motherboard problems it looks like.flash the BIOS or get another board.because the PSU cant be so bad that actually will change those small voltages which is control by the BIOS.