How do I get my computer monitor to turn on and off at the same time as my computer (desktop)

I have a desktop computer running windows 10 with a GTX660 graphics card connected to an HDMI monitor.

I recently changed my computer. When I turned on my old desktop computer, it would automatically turn on the monitor. When I turned it off or put it in sleep mode, it would automatically turn off the monitor. Literally all the computers I've seen worked this way.

My new computer does not do that and I don't understand why.When I put my computer into sleep mode, the monitor turns off. Then, a few seconds later, the computer's fan goes silent and then the monitor turns back on and shows "Check cable signal".I need to manually turn the monitor off and to manually turn it on the next time I use the computer, which is annoying.

I should also mention that, I could wake the old computer from sleep mode by pressing a key on the keyboard or mouse, and the new computer no longer does that, I need to manually press the power button.

If I don't interact with the computer for a few minutes, the monitor turns off, and it turns back on when I move the mouse or press a key on the keyboard.

So far, it looks like :

1. The computer can tell the monitor to turn on or off
2. There is something wrong with sleep on this computer
3. When the computer is off or sleeping, the monitor believes that it is on, and expects a signal.

I would like to know :

1. How does the computer tell the monitor to turn on or off ? Does the computer simply stops sending the HDMI signal or does it uses some sort of other signal in the HDMI port like hot plug detect, CEC, DDC ?

2. What do you think is the cause of my problem ?

• Improper Windows settings
• Improper BIOS settings
• Improper graphics card settings
• Graphics card driver problem
• Graphics card does not support this feature
• Motherboard does not support this feature
• CPU does not support this feature
• Monitor does not support this feature (it did work with the old computer and the same monitor)
• Defective HDMI cable
• Power supply problem
• Something to do with the other problem (keyboard or mouse can not wake up the computer)
• Incorrect voltages on HDMI port when the computer is sleeping or off, making the monitor believe the computer is on