randome sleep/shutdown problem - CX600M issue?

Asus P5Q Pro motherboard

E8500 Core 2 Duo

2 x 2GB OCZ Fatal1ty edition DDR2 RAM

on-board sound

Corsair CX600M PSU (about 18 months old)

EVGA GTX480 (refurb, less than a year old)

OCZ Agility 4 SSD boot drive (2 years old)

WD 74GB Raptor HDD (10 years old)

WD 640 GB HDD (6 years old)

Windows 7 Home (64 bit)/Windows 10

 

Obviously this is an older build, but the PSU and GPU were both replaced last year after failures, and the SSD is a couple of years old. The system ran reliably until a couple of months ago, when it suddenly started either shutting down, or going to sleep even as I was typing. Sometimes it will resume if I wait until all fans and everything stop before pressing another key. Other times the screen will go black and the fans still run, but the only way to recover it to do a hard reset or switch the power off. I was running Windows 7 when this started, but upgraded to Windows 10 a few days ago and this problem tagged along. It usually happens while I am using web browsers or MS Office, such as Word or Excel, but so far has not ever happened while playing games that really stress the system.

 

Sometimes it will do it several times in a day, sometimes within minutes of starting up, then I can go several days without issues.

I cleaned out the PSU, GPU and CPU cooler with compressed air, and made sure all case fans are clean and operating.

I ran the Windows memory test on reboot, and no issues were reported, and have tried running one stick at a time but it still happens.

I have checked and rechecked power settings. I don't use a screensaver, the monitor is set to shut off after 20 minutes of inactivity, and the hard drives are set to never shut off.

I did a clean install of the graphics and sound drivers. My mobo/CPU combo does not have integrated graphics, so I cannot try running without a graphics card.

All drives check out OK on SMART and with the Windows 10 error checking utility.

Recent scans with Avast, Panda online tools, Super AntiSpyware, MalwareBytes Anti Malware, and Windows Defender don't show anything.

The Reliability Monitor shows some issues, but does not log anything that I can see when this happens. But I am not the best at reading it, either.

 

If there are any logs or anything I can upload that will help, I will be glad to.

 

On another forum someone suggested the PSU, and I have seen threads hear about similar issues. I’m open to suggestions, and don’t really know how to determine what the issue is. I do not have a spare PSU lying around that has enough connectors for the GPU, so I can’t really test that way, unless I just buy a new PSU, but this one is still under warranty.

 

Thanks in advance!

Well, that stinks, too. :) I am trying to save up for a new Mobo/CPU/RAM, but I still have a ways to go.

 

Someone on another forum suggested it may be the old Saitek Gamers keyboard. It appears in device manager as three devices, and I have had issues with some games (Need for Speed: Hot Pursuit won't even start until I unplug the keyboard). I might try swapping it out with an OCZ Alchemy I have here and see if the issue continues.

I think changing my keyboard did the trick. 11 days without this happening again! But I sure did like that Saitek a lot more than this OCZ.