PC switches off randomly

  Afaleeds 00:46 12 Apr 2015

My pc with Fujitsu Siemens W26361-W1622-X-03 Intel Motherboard switches off every time windows tries to load but will sit in bios all day happily without switchng off.

The problem started with it switching off randomly but only occasionally during normal operation in windows. Now it will always switch off whenever windows tries to load but not necessarily at the same point . I tried everything to isolate the problem but just don't seem to find the right cause. I am 100% baffled...

Any ideas / thoughts will be welcome

  robin_x 02:27 12 Apr 2015

Could be overheating. Open the case and de-fluff.

If you can get it to boot, install Core Temp.

Does it Blue Screen briefly or just go dead black?

Could also be the PSU or Memory.

Try one stick of memory.

  Afaleeds 08:31 12 Apr 2015

Thank you...

I have tried a different psu, taking one ram out, disconnected hard drive and used dvd drive to install new O/S from drive at the same time, disconnected DVD drive, reapplied thermal paste, inspected m/b for cracks, moved leads around, directed external house fan at heat sink, disconnected switch button, .... So many things... But it will memory test fine and sit in bios all day without switching off until I try to load windows7.

It switches off, screen goes blue but no messages or and characters of any kind. Please explain what having a blue or black screen indicates... Many Thanks

  Fruit Bat /\0/\ 10:19 12 Apr 2015

Try a startup repair

How you access the repair options will depend upon whether you have a Windows installation disk or whether your operating system came pre-installed by your PC manufacturer.


If no repair options are available your PC manufacturer may have replaced the tools or customised them. Check your Computer Manual before proceeding as another key may be needed to access the Repair/recovery options.

  1. Start your PC

  2. If your PC has one operating system Press and Hold the F8 key as your PC starts. If the Windows Logo appear you will need to start again

  3. If you have a dual boot system a Boot option menu will appear. Highlight the Windows operating system and Press the F8 key

  4. An Advanced Tools menu options screen will now appear

  5. Highlight the repair Your Computer option and Press Enter

  6. Select a keyboard layout, and then Click the Next button

  7. Next select your user Name and Enter your Password, then Click OK

  8. The recovery options should now appear

Windows Installation Disk


Make sure your PC is set to boot directly from the Windows DVD, most modern PCs are set this way. With older machines you may need to check the PC's BIOS

  1. Start the PC

  2. Immediately insert the Windows DVD into the DVD drive

  3. A Black screen will appear with the words 'Press any key to boot from CD or DVD', Press Any key to start the booting process

  4. The 'Windows is loading files' screen will now appear with a progress bar.

  5. After a few minutes the Microsoft copyright window ill appear and another small progress bar will be visible

  6. You will next see a Blue curtained screen

  7. Next the Language option screen will appear Select your language and keyboard language and the Click the Next button

  8. At the bottom left of the next screen - the Install screen, Click on the Repair Your Computer option

  9. The System recovery options will now search for your Windows installation

  10. Once the Windows installation has been located, Highlight it and then Click the Next button

  11. The set of recovery options now appears, Click on the Option you require and follow the on screen prompts

Repair / Recovery Options

  • Startup repair - This automatically fixes problems that are preventing Windows from starting
  • System Restore - This will Restore Windows to an earlier point in time
  • Windows Complete PC Restore (Available in Windows Vista Business, Enterprise and Ultimate editions only)- If you don't have a backup then don't use this option This will completely restore your entire PC - programs, system settings and files - from the back up that you have previously created. Any other data will be lost
  • Windows Memory Diagnostic Tool - This checks your computer's memory hardware for errors
  • Command Prompt - This opens a Command Window
  Afaleeds 10:23 12 Apr 2015

Thank you but it will not stay switched on to reach repair. As I mentioned, I tried installing a new windows...it just switches off at varying point when I send it beyond bios ... So I am certain that it is a hardware issue... But can't pinpoint what....

  wee eddie 11:30 12 Apr 2015

Where are you getting your copy of Windows from?

  Afaleeds 13:50 12 Apr 2015

From the Microsoft website as I have the windows 7 sticker with the code on it. But is this relevant to this problem?

  wee eddie 13:55 12 Apr 2015

Only if your download of Windows is corrupt

  wee eddie 13:59 12 Apr 2015

or incomplete.

  OCTCORE 14:16 12 Apr 2015

Can you force disk check ?

Run task manager and see whats running, maybe a virus or malware.

Is the cpu heatsink loose.

Did this just suddenly start one day and for years its been ok ?

  Afaleeds 15:15 12 Apr 2015

I need technical info please.

First, how is the cpu temperature measured and could the temperature sensor be faulty? Is it like a thermocouple that can be changed?

Also, is it possible for the heat sink to stop conducting heat even if it is making good contact with cpu? I ask this because I let the pc run in bio for a while and I shielded the fan from throwing air at the sink but the sink did not show any warmth at all... Surely there should be some warth there if no air is flowing past it....

any ideas please?

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