No restart, optiplex 755 Small Form Factor Computer

any ideas?

Hi Nissim,

I would suggest you to restore BIOS to defaults. You may follow the steps below:

• Power on and tap 3-4 times at Dell logo to access system setup
• Go to ‘Load Defaults’ listed under ‘Maintenance on left side and press
• Press to ‘Save and Exit’ from BIOS.

You may run the hardware diagnostics on the system to check for the hardware functionality. You may follow the steps below:

• Reboot and press F12 to enter the Boot Menu
• When the boot device list appears, highlight Diagnostics and press Enter
• The computer begins to run the Pre-boot System Assessment, a series of embedded diagnostics that perform initial testing on your system board, keyboard, hard drive, and display
• In case any hardware component is bad, you will get a corresponding error

Please refer to the link: http://dell.to/1bal3Uh.

Keep me posted with the results. I will be glad to assist further.

Thank you very much for your answer.

I already did all that, restore BIOS to defaults was the first thing, the second thing is to rest the bios by removing the battery, I run the hardware diagnostics and it pass everything. as I mention the computer is working fine with windows 7 64 the only problem is it won't restart but shut down no problem.

I'm electronic technician I thought someone came across this problem and can lead to the part that causing the problem, probably a short or disconnected transistor in the motherboard.

Many thanks for the answer.

Hi Nissim,

I would suggest you to do a clean boot using ‘msconfig’. You may follow the steps below:

• Press ‘Windows’ key + R on ‘Desktop’ screen.
• Type ‘msconfig’ in run box and press .
• Click ‘General’ and then check ‘Selective Startup’.
• Now check if the system is getting the restart option.

You may try to boot in ‘Safe Mode. Please refer to the link: http://dell.to/1cdf2vi.

Hope this helps. Feel free to reply for any further questions.

thanks for the answer

its new installation and yes i did a clean boot

as I said before there is no point to look at the operating system the problem is on the computer hardware it can't even restart during the installation every time that the operating sys try to restart during the installation i need to restart it from the main power bottoom.

if someone knows which part or which transistor responsible for restarting in the motherbord or if someone can tell me where to find schematic diagram of this computer it will help

again thanks for trying to help 

Hi Nissim,

I would suggest you to try and reseat the CMOS battery of the system.

For owner’s manual, you may refer to the link: http://bit.ly/ZXm4Kg.

Hope this helps. Please feel free to reply for any further questions.

thanks for the answer

The first thing I did is to reset the CMOS battery of the system.

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thx

Hi Nissim,

It seems the issue is with the system BIOS and it is not able to interact properly with the hardware maybe due to any external peripheral. I would suggest you to remove all the external components connected with the system and check if the issue still persists.

If it persists, then the issue is with the motherboard and it is needed to be replaced.

Keep me posted with the results. I will be glad to assist you.