Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Occasionally, when I'm away from my computer for about 5 minutes, the computer screen will go black and all USB devices (keyboard/mouse) will lose power. Attempting to move the mouse or pressing keys does not 'wake up' the computer.

This only started happening a few days ago but I'm not sure what changes I did could have caused this and I uninstalled programs (one by one) I installed before it started happening, but still having the same issue.

The one thing I noticed different about my computer since it started happening is i've been getting random survey popups from

I ran Microsoft Security Essentials scan, it picked up some Java related malware, I removed it but still the same issue. I'm running MBAM right now and will run SAS after.

Edit: I just updated drivers for motherboard and video card and ran virus scans, still having the same issue.

share|improve this question
It doesn't sound like something software- (and therefore malware-) related. Check that it's not getting hot, and your power saving settings are sane. I've seen those reset themselves on some hardware. – user3463 Feb 9 '11 at 6:16
@Randolph - I just checked the windows power saving settings/plan and everything looks normal. I have nothing set to turn off screen/hard drive. I'll keep an eye on the CPU, but this only happens when the computer is idle. It has not happened while I'm using the computer. – Omar Feb 9 '11 at 6:22
I've seen weird behaviour on Vista (not Windows 7) where the screen card and network drivers can cause odd behaviour with idle blackouts like this. Did you install any new Windows Updates recently, specifically with drivers? If so, you may need to roll back. EDIT: Also, what happens if you unplug and replug the keyboard when this happens? – user3463 Feb 9 '11 at 6:24
@Randolph - Unplugging and replugging does nothing when it blacks out. The only thing I can do is force shutdown or restart the computer. – Omar Feb 10 '11 at 0:02
Whats virus scans have your run? It very well may be malware related. – Not Kyle stop stalking me Feb 10 '11 at 2:41

How are you waking up your computer when it goes to sleep (black screen)?

Temperature can cause your problem, as can several other things, but since temperature is easy to monitor, I'll make two recommendations on temp monitoring:

and a program which supplies much more info about other matters but which is a convenient program from temp monitoring is:

Both of these programs are free. I've used both ,and in fact, coretemp is running at this very moment on this machine.

Following is info on POWERCFG which you run from an elevated command prompt:

Devices which you can enable/disable wake



C:\>powercfg -devicequery wake_programmmable
Realtek PCIe FE Family Controller
HID-compliant mouse (004)
TOSHIBA Software Modem

Enable a programmable device to wake your machine



C:\>powercfg -deviceenablewake "TOSHIBA Software Modem"

List of all devices which can wake your machine

powercfg –devicequery wake_armed


C:\>powercfg -devicequery wake_armed
HID-compliant mouse (004)
TOSHIBA Software Modem

More information for you

  • This will bring up the device manager.
  • Now go down the tree till you find Universal Serial Bus Controllers.
  • Take a look at each and every one of the USB Root Hub entries.
  • Right-click on the USB Root Hub entry.
  • choose Properties
  • Power Management tab
  • UNCHECK Allow the computer to turn off this device to save power.
share|improve this answer
Running speccy, I see my CPU is at 36 degrees C and video card is at 44 degrees C. Both look fine. The screen goes black ONLY when the computer is idling - never when I'm using it. In regards to what wakes up the machine, ALL usb devices lose power when this happens, so moving the mouse or pressing keys does nothing. – Omar Feb 10 '11 at 0:04
@Omar -- did you read this: "UNCHECK Allow the computer to turn off this device to save power." – Daniel R Hicks May 9 '12 at 12:02
up vote 1 down vote accepted

My tower is a Coolermaster HAF 932 and the problem was with the front-panel.

It seems there's some wiring issues that causes any type of static to trigger something in the motherboard.

It turns out that when I would walk away from my computer and pass by my tower (within inches) the computer screen goes black. I only assumed the issue happened when it was idle because I never looked back immediately after I left my computer.

I was able to reproduce the issue by just moving my hand in front of the front-panel which caused the black screen.

I called Coolermaster and they replaced the front-panel and it works fine.

share|improve this answer
That's a weird issue, never heard of something like that before. – Simon Verbeke May 9 '12 at 14:26

check your power option (right click on desktop -> go to screen saver tab -> press power option bottom )

share|improve this answer
Already checked this. Nothing is set to sleep/hibernate/turn off. – Omar Feb 9 '11 at 21:17

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.