The computer is turned on for a while, and the screen is black, only a short horizontal line appears

The problem can be between the monitor or the graphics card;

So you have to distinguish between the graphics card and the monitor first; You can use the elimination method to find the problem.

When you fail, you can move your monitor to a friend's computer and give it a try.

1.The problem of the display should be the problem of the display high-voltage board or the simple lamp!

Specific points: due to the ignition of the lamp to the high-voltage board over-current protection, or the instability of the components on the high-voltage board itself!

2.If there is a problem with the graphics card, you can check whether the fan of the graphics card is rotating normally or remove the graphics card to clean and wipe it before installing it, if not, replace the graphics card.

The system boot file is missing and needs to be reinstalled.

Reinstall the system, I usually do this when I have a problem.

This is obviously a hard disk problem, brother, there is something wrong with your system!

As soon as the computer is turned on, a black screen appears, and the fault of the black screen is that the bootloader of the disk is missing and the system cannot be booted normally. You can use the system disk to repair the operating system.

The boot screen is black, and a flashing white underline appears in the upper left corner of the screen, the reason is that the master boot record MBR of the hard drive is missing.

The Master Boot Record MBR is located in the boot sector of the hard disk, and when this record is lost, the computer will not boot regardless of whether there is an operating system installed on the hard disk or not.

This situation can be solved by reinstalling the system. Reinstalling the system will rebuild the MBR, and after the installation is complete, the computer will boot up normally.

In this case, check whether the boot device in the BIOS settings is a hard disk as the priority boot device, if not, change it to a hard disk to start first, check whether there is a USB disk, mobile hard disk and other devices plugged into the computer, unplug it and restart it, if it still can't be solved, reset the system to try.

Generally, you will choose to start Windows normally, but this prompt will appear the next time you turn on the computer. The reason for the Windows error recovery prompt is usually caused by the recently installed hardware or software.

The specific steps to solve the problem of "the computer keeps turning on the black screen and there is a horizontal flashing in the upper left corner" are as follows:

1. Right-click on the blank space of the computer desktop, and the right-click drop-down submenu will pop up, and find "Screen Resolution" in the submenu.

2. Click "Screen Resolution" to pop up the screen resolution setting window page, and you can find "Advanced Settings" on the page.

3. Click "Advanced Settings" to pop up the properties window page of the monitor and adapter, and "Monitor" can be seen in the menu at the top of the page.

4. Click to enter the tab page of the monitor, and you can see the "screen refresh rate" on the page.

5. Re-set the refresh rate to solve the problem of flashing when the computer is turned on.

This solves the problem that "the computer keeps turning on the black screen, and there is a horizontal flashing in the upper left corner".

I entered the BIOS or MS-DOS interface.

You can restart the computer to see if you can enter the system normally.

If it doesn't work, you need to reinstall the system to solve the problem.

The easy way is to reinstall the system.

The black screen you mentioned when you boot up, and the horizontal line flashing in the upper left corner of the screen, is caused by the damage or loss of the master boot record of the hard disk.

The Master Boot Record is responsible for selecting the specified operating system and booting after the computer hardware self-test, after the BL boot control is handed over to the hard disk.

There is a flicker, and the hard drive has not been able to boot. You can only use the system disk to restart the computer, reinstall the system, or repair the boot.

Eighty percent of the computers cannot enter the system and are stuck in this part of the self-test. You can only use a USB flash drive or CD-ROM to reinstall the computer's system or replace the computer's hard disk with a normal hard disk.

Maybe there is a problem with the system, you can try to restart the computer to see if the problem still exists, if it still exists, you can change the display and try again.

It should be that the system is faulty, and you can directly reinstall the system.

An error occurred to boot the bootloader.

This requires the use of a system repair tool, PE system.

After the computer is turned on, the horizontal bar in the upper left corner flashes, it is likely that the system is not booted correctly, or it is possible that the system is damaged. Solution 1: Enter safe mode, restart the system, and then keep pressing F8 during the startup process to bring up the advanced boot options, press the arrow keys and select [Latest Correct Configuration (Advanced)].

Solution 2: BIOS adjust the boot order, adjust the hard disk to the first boot item, press F12 to save, and restart. Solution 3:

To repair the MBR boot sector, you need to have a USB flash drive PE boot disk, enter the PE system, double-click the [DG Partition Tool] on the desktop to open the DiskGenius partition tool, select the hard disk where the system is located, rebuild the Master Boot Record (MBR), after rebuilding the MBR, continue to click [Boot Repair Tool] on the desktop, and follow the prompts to repair the system boot.