System hangs once per day, no error message

27 Aug 2014

Hi. I was wondering if anyone could assist me in figuring out a problem with a computer running Windows 7?

The OS hangs once per day. There is no error message, it just hangs after about 15 mins from starting the computer (and only once per day; after I reboot, the system no longer hangs). It also seems like it's a problem with windows explorer, because sometimes the task bar becomes unresponsive and I'm unable to use CTRL+ALT+DEL to bring up the task manager, but I can still switch to open application windows for a minute or two and they work normally, until the system hangs completely.

I've looked at everything that I could think of and searched online for help. Win 7 is updated. I've checked any weird applications or processes running. I've checked the task scheduler to see if anything strange was set to run on boot up/once per day. I downloaded every troubleshooter I could find on the Win 7 site, no problems were detected. I used disk clean up. I checked for any security problems. The only thing I didn't try was to restore the installation, because the computer had an OEM installation of Win Vista which I later upgraded to Win 7, so I only have the Win 7 update DVD, and I'm not sure that'll work or if I have to create some installation discs somewhere?

The curious thing is that I checked for recently updated software and basically uninstalled everything that I had updated the last few months (Java plugin, Microsoft .NET and Flash). This seemed to fix the problem and I had no need for any of those, so all good. But two weeks later, the problem returned. So I have no idea. Maybe I have some weird trojan on the computer and the person exploiting it went on vacation for two weeks in August?

Can you help or give me any pointers? Please let me know if you need me to post any information.
Thank you very much!

Tookeri · 27 Aug 2014

Have you tried booting to Safe Mode and wait 15 minutes?

You could also try a Clean Boot: How to perform a clean boot in Windows

Safe Mode runs with minimum requirements, drivers etc.
Clean Boot assumes Windows itself isn't the problem and runs without 3rd party stuff.

You could also try Process Explorer from Sysinternals(Microsoft). It'll list all running processes and has an option to check each file on VirusTotal, a multi-engine scanner with 50+ AV's. If you launch it as Administrator it will check all processes incl. those running as system and with high integrity. If the VirusTotal column shows for example 0/55 it means no AV detected anything out of 55 different AV's. If any process shows something else than 0 you can click on it to view the report on VirusTotal. See the report to find out if perhaps it's a false positive or a malware. Process Explorer
A review with screenshots here: http://www.ghacks.net/2014/01/30/pro...total-support/

28 Aug 2014

Hello, thanks for your reply and advice.

I have tried safe mode and waiting, and the problem didn't occur. I just tried your suggestion of performing a clean boot, so far so good, but because I had already logged into Windows, I might try again tomorrow to make sure (it's difficult to troubleshoot this also because the problem really only occurs once per day).

I will check Process Explorer also, thank you.

But what to do next? Any idea how I can pin point the problem (for instance, if it's a process or service that's causing the problem, how can I identify it)?

Thank you!

Tookeri · 28 Aug 2014

You can try and add 1 item at a time from the clean boot instructions where you unchecked items in msconfig.

If it's caused by malware, Process Explorer will help you with the VirusTotal check. A tip: while Process Explorer is running, start the programs you usually use, one at a time if you prefer, and then wait for the VirusTotal result for that program/process. That way you'll check more than just the processes that autostarts.
In Process Explorer go to the Options menu - VirusTotal.com and select Check VirusTotal.com. If you have any processes that hasn't previously been scanned on VirusTotal you could also select Submit Unknown Executables. If not all information is shown for all processes, go to File menu - Show Details for All Processes.

Have you checked Event Viewer for any errors or warnings around the time it hangs?

A hacker with a 2 week vacation, that was funny, but let's hope it's not the issue here

29 Aug 2014

Thanks for your help. It's going to take a long time to check each item, unfortunately. The event viewer doesn't seem to list anything before the system hangs, afterwards, it logs the forced reboot. It does log a bunch of WMI-related errors, but not at the time of the hangup.

I had also tried checking with process monitor, but there doesn't seem to be any strange internet activity, although I could be wrong. The CPU seems to be busy all the time though, and sometimes goes a little haywire, I thought maybe due to one of Windows' background processes (like search indexing, etc.), so I also disabled everything that didn't seem necessary, but the problem persists.

I will try process explorer this weekend and see if there's any progress in figuring out the problem.
Thanks!

08 Sep 2014

Hello!

Just thought I'd share that I've used the task scheduler to disable all non-essential tasks that were loaded daily on boot up and the problem went away. It's difficult to pin point the offending process though.

Thanks for the help.