Computer wont POST and black screen

[Stribor50]

My comp displays d-sub no signal detected going into power save mode.   I removed all ram and left  only one but that didnt change anything.  Tried different cables and monitors that i know work but result was still black screen.   I dont hear any beeps.  
i can hear hard drive and fans running and i can see red led light amd orange hard drive light at the front of the pc. 
i also remove video card and connected monitor to onboard graphic but that brings conputer into. Infinite restarts.  Is there a way to boot with on board graphic on this machine?

[itsmyname]

@Stribor50  -- that brings computer into. Infinite restarts

Leave the add-in video-adapter out of your computer, to use the integrated graphics.

After a few consecutive "failed" restarts, Windows 10 should open to a "Recovery Window".

If it does, try using "System Restore" to time-warp your computer back to a date/time when it was working.

If that Recovery Window does not open, boot your computer from a Windows 10 Installer DVD (or from USB memory-stick).

If necessary, make one: Download Windows 10 (microsoft.com)

Boot from it, and choose "Repair".

Get back to us, if you have a problem.

[Stribor50]

This is actually Windows 8. I made recovery image of Windows 8.1 on USB and put it into one of the front USB ports and booted the computer without video card inside while connected to onboard graphic and this caused infinite restart. I turned off the computer by pressing and holding  the power button. I put back video video card inside and booted the computer. This started computer with no issues (no restarts) but still black screen with "d-sub no signal going into power saving mode"

[itsmyname]

@Stribor50 -- does your computer have more than one DSUB video-output connector?

What type of video-cable are you using (VGA-VGA, DVI-VGA, DVI-DVI, HDMI-DVI, HDMI-HDMI) ?

Does your monitor have multiple inputs (VGA, DVI, HDMI) ?  If so, you have to configure the monitor to "listen" to whichever input-connector that is connected to your computer.

[Stribor50]

@itsmyname - - computer has DVI, DP and HDMI port. Monitor has VGA port.

I am connected to the computer on DVI port using VGA-VGA cable that has DVI adapter on the other end.

I know that this works because I tested it by simply unplugging this cable from DVI port on the non-displaying computer and connecting it to my work computer on DVI port and I instantly see windows on this monitor.

[itsmyname]

@Stribor50  -- computer has DVI, DP and HDMI port

Are all these ports on the add-in video-card?

Since your computer has integrated graphics, what integrated ports does it have? VGA? DVI? HDMI? DisplayPort?

Can you borrow a screen with DVI input, and connect from DVI-output on the add-in card to DVI-input on the screen?

[Stribor50]

@itsmyname --  DVI, DP and HDMI ports are all on dedicated video card

Iintegrated video card has two DVI ports that have been blocked by black cap with words "do not remove". I removed these two.

You asked "Can you borrow a screen with DVI input, and connect from DVI-output on the add-in card to DVI-input on the screen?"

Monitor already has DVI input and I connected DVI-output from add-in card to the DVI-input on the monitor and still black screen. I also did this from on-board video card and computer keeps restarting.

I used spare computer that had DVI output and I connected it to DVI-input to the same monitor and works fine. I used same cable. 

I also used different monitor (I use this monitor for work daily which works fine) that I have and  I connected it to the computer in questions on two port (DP and DVI) on the dedicated video card.

Is it possible that dedicated video card is finished and on-board video card is blocked in BIOS? At this point where I am I am curious to know is the computer even working. When I turn it on fans are spinning, I see red  LED right at the front of the computer, i also see hard drive yellow light flashing for a bit and bottom of the mouse (USB wired)  is lit up.  This computer has 5-6 USB ports and mouse is lit up when i connect it to each of these.  USB wired keyboard however is not lit up when I connect it to each of these.

[Stribor50]

I also unplugged everything and left one stick of RAM, CPU and heat sink and computer just keeps restarting and not video output to the screen.

[Bennett78]

Press and hold the power button until your computer turns off. 2) Unplug the video cable which connects your monitor to your computer. 3) Check the port connectors on your computer and on your monitor. If any connector on your device is bent or damaged, you'll need to take the device to a repair shop.

greatpeople

[itsmyname]

@Stribor50 -- Is it possible that dedicated video card is finished

Yes, if it is properly "seated" in the slot, and none of the monitors that you attach to any of its ports produce any output.

> and on-board video card is blocked in BIOS?

For most motherboards, the physical presence of an add-in video-card causes the onboard video to be bypassed.  Remove the add-in video-card, and connect your monitor(s) to the 2 onboard video-ports, and then see if either screen displays anything when you power-on the computer.