Can't shutdown, reboot or log out on windows 8.1

Hello,

Since a week I can't shutdown, reboot or log out from windows 8.1 . The system stay stuck sometimes at "installing update 2 of 8" (I tried to disable windows update and when I do that the system is generally stuck at "Please wait..." with the points moving in circle). Doing a CTRL+ALT+DEL on this screen make the system freeze (points are not moving anymore).

I have done a "sfc scannow" command and I have no error.
I tried to boot in safe mode and everything is working fine there: I rebooted without problem.

However since I have done that I have a black screen each time I boot and I need to kill "explorer.exe" and create the task to see my desktop but it is another problem...

I also tried "powercfg /energy" and the command stayed stucks at "Observing system..." during an hour. When I close the cmd et retype "powercfg /energy" I have an error: "Unable to open ETW session... Session ETW is already in use...".

I also tried to create a new user on my computer but the system crashed even for that...!

I have no more idea how to detect where the is from. I tried to stop all non-windows services and it didn't made the trick. It should be a software maybe but I don't how to find which one... (it's not a virus or malware I already scanned my computer)

Thanks anyone who could help me.

Looks like its time to do a Refresh or reinstall Windows, back up your data before hand.

A refresh as Nucci suggested might well be the easiest answer.

If you want to take the long road. please follow the instructions in this tutorial:
http://www.eightforums.com/bsod-cra...e-screen-death-bsod-posting-instructions.html

The fact that Safe mode works well indicates either a startup item or hardware / driver.
installing update 2 of 8 isn't very informative for trouble shooting purposes.

Please attach C:\Windows\WindowsUpdate.log

You mentioned disabling non-Microsoft servies, but you didn't say anything about startup itmes.

Run System Configuration

1. Services tab
   Hide all Microsoft services
   Press the [Disable all] button
   
   
2. Startup tab
   Press Open Task manager
   Disable all except your Anti-virus application (if an Anti-virus application is in the list, not all start this way)[
   
   Close Task Manager
   Press the [Ok] button on System Configuration
   
   
3. Restart your machine

There are more things to try, but a Refresh might be easier and faster.
See: http://www.eightforums.com/tutorials/2293-refresh-windows-8-a.html

Read though the tutorial and ask any questions before you do the steps.

Follow either Option One or Option Two - which ever is easier for you.

I would also vote for a refresh. If you have any purchased programs installed, make sure you retain the product keys because you will have to reinstall the programs.

I'd even vote for a fresh install. And afterwards frequently create system images with a backup software so if you are ever in the same situation again you can simply restore a system image. Seriously, at least do a refresh or better a fresh install. It will cost you much less time than trying to fix your problem. And even im you invest countless hours in trying to fix it there is absolutely no guarantee that you will ever manage to actually fix your Windows.