The computer startup screen may be black due to the following problems:

1. Monitor connection problem, check whether the monitor is connected correctly and whether the switch is turned on.

2. For computer problems, observe whether the computer has a startup sound and whether it starts normally.

3. Check if there is any problem with the memory. You can try to replace the memory module, or check if it is loose.

4. There may be a system problem. You can try reinstalling the system to solve it.

5. Monitor failure. If the above reasons are eliminated, the monitor is faulty. It is recommended to send it for repair.