This is a case that often happens on desktop computers and does not happen on laptops. Display entering sleep Mode error is the case when the image signal from the computer cannot be transmitted to the screen. There are cases where after booting, the computer displays entering sleep mode. There are also cases where the computer displays entering sleep mode after the user wakes the computer from sleep mode or while using it normally.
According to my research, there are many errors with similar symptoms and solutions to Display entering sleep mode. There will be some common names such as no video input error, enter sleep mode error, Monitor going to sleep error or No HDMI cable error.
Display entering sleep Mode is a notification indicating that the computer screen will be put into sleep mode when it does not receive a signal from the computer. When this message suddenly appears on your computer screen, it may be due to the following reasons.
The first reason why your computer says Display going to sleep. It could be because a component on the computer is loose or damaged.
Now check to see if the caps lock key light is on or not. If the light is still on, it means the computer is fine and you need to check the wires and ports connecting to the screen. If the caps lock light does not light up, the computer is likely damaged and it is best to take it for inspection.
Loose RAM is also one of the main factors causing the Display going to sleep error screen. This may originate from improperly plugged in ram or dusty ram pins causing poor contact.
In this case, if you have experience disassembling computers. Try removing the RAM to clean the connection pins. You can also use a soft brush to clean the ram slot on your computer. Then install the ram in the correct direction, turn the ram hold lever and restart the computer to see if the error persists or not.
Similar to RAM, the video card is also one of the possible causes of the computer reporting the Display entering sleep mode error. However, this case may be more serious because your video card may be faulty or damaged.
At this point, the only solution you can try is to clean the video card's pins and slots and then plug it back in. If the video card has an auxiliary power source, you must plug in the power cord. In case the computer's CPU has integrated VGA onboard. Try plugging the cable into the video output port on the mainboard to see if it outputs the image normally.
In my opinion, Display entering sleep mode errors are mostly caused by loose wires or loose RAM. Therefore, with the methods I introduced above, I believe you will be able to fix the error. In the worst case when the above methods don't work, you can bring your computer to check!