No signal on monitor, PC shuts down instantly

RayCharlZ - May 13, 2017 at 08:58 AM
Ambucias Posts 47356 Registration date Monday February 1, 2010 Status Moderator Last seen February 15, 2023 - May 13, 2017 at 05:39 PM

When I try to turn on my desktop computer, all lights turn on and the fans are working but the monitor displays "no signal". If I press the button On/Off, the computers shuts down instantly. This computer worked perfectly Yesterday, it was shut down normally, I didn't move it.

If I unplug the VGA port, the monitor displays a message "please check cable connection" but it displays "no signal" when it is plugged. I don't have better results with the HDMI port with a TV screen. I have tried to reseat all internal connections, I have unplugged the RAM module and plugged it on the other port, I have replaced the CMOS battery. I have replaced the SATA cables by other working cables. I can hear the hard drive working when computer is turned on. I have tried to connect the hard drive to SATA 0 to 3 on the motherboard. I tried to boot on a liveUSB : it is recognized (blinking light) but the computer doesn't start on it. I have cleaned all dust particles.

None of the above gave any satisfying result... As my motherboard has no speaker, I don't have the luck to hear any beep signal. Do anyone have any suggestion about how to repair it?

Thank you in advance for your help,

2 responses

I've finally found the solution, so here is the explanation in case someone else gets the same issue:

I noticed that I have 2 VGA ports on my computer: the cable needs to be plugged in to the graphic card VGA port, not to the motherboard: otherwise, there is no signal. My computer turned down immediately after pressing On/Off button because after replacing the CMOS battery, the BIOS was reseted and it asked what to do about it: reset default and restart or reset default and continue boot. As the BIOS didn't even launch, the computer directly shutted down when button was pressed. As soon as I had access to a signal on my monitor, it was easy peasy to correct. Finally, the initial problem came from a windows update (I didn't remember it updated last time I used it) that went wrong. A little restoration and voilà, brand new!

Good luck to anyone having the same problem.