Last week at this time, after the child's computer went to sleep and was awakened, it directly displayed a black screen. Then it restarted and scanned the hard drive before entering the system. After a few minutes, it blacked out and froze. When restarting, the power light was on, but the hard drive was not reading or recognized. There was no alarm, and it couldn't be shut down. It could only be turned off by cutting the power. Once powered on, it started itself. This happened twice, and I didn't dare to power it on again. I disassembled it, removed the memory, and reinstalled it, but the problem persisted. I also reinstalled the hard drive cable with no effect, then removed the memory and changed the slot, but it still didn't work. The initial judgment was that it might be a hard drive or boot issue, and the worst-case scenario could be a BIOS problem since it didn't display BIOS information and remained black. It could also be a power supply issue.
The next day, I found some spare parts: one memory stick, one hard drive, and one power supply. After changing the memory, it started to beep. Five short beeps, beep beep. It was likely a memory issue, but the old memory didn't beep. Strange. I replaced it with a hard drive I previously used for RAID 0. Plugging it in still showed the same issue, indicating it wasn't a hard drive problem. Then I changed the memory again. This time, when I powered it on, the motherboard fault light was blinking, and it was quite noticeable as an ambient light. I noticed the CPU power supply connector was quite loose, so I thought about directly changing the power supply. I didn't remove the old power supply; I just unplugged the motherboard power, hard drive, and CPU power connectors. I connected another power supply's connectors. It still beeped. Both memory sticks were beeping. I wiped the original memory stick and plugged it back in. It worked well. It beeped once during self-check and entered the system.
Upon entering the system, it prompted me that the configuration file was missing. I didn't pay much attention, thinking it would probably be fine after another restart. Then I shut it down to test whether the power supply had issues. I replaced it with the old power supply, but it still showed a black screen. The power supply was faulty. I then removed the old power supply and replaced it with another working old power supply. When I powered it on again, it lit up. After entering the system, it still prompted a configuration file issue.
In the evening, I had some time and wanted to try to repair it. There were many methods online; the system repair and restore mode took over an hour but did not fix it. A command scan also did not repair it. Since the child's computer had few installed programs and custom configurations, I decided to reinstall the system directly. After a while, I installed Steam, Chrome, and Minecraft. This time, I installed a newer LTSC version that came with Edge. I didn't install the motherboard's built-in network card driver, and everything was normal until I restarted the computer, after which it couldn't connect to the internet. I then installed the motherboard's built-in network card driver to restore connectivity.
Then the child used another low-spec laptop to occasionally watch videos, and until this morning, he wanted to play Terraria. I installed it for him, so he used the repaired desktop. After twenty minutes of powering on, it suddenly blacked out, but restarting it was normal. After playing for more than an hour, when I asked him to write an English test, the computer blacked out again. I checked the information and found that the causes of black screens almost involved all hardware. Well, I will continue to observe. It might be a power supply issue. A new power supply is expensive, so I might as well sell the CPU, memory, and motherboard. I'll look for other second-hand complete computers. I will continue to observe and check for any updates in the evening.
Additionally, I found out today that there were no cloud saves for Terraria on Steam; I had to click to sync to the cloud. The child played from the beginning because of this. I will check for saves in the evening. The achievements are still there, but the saves are gone.
The configuration is i3 9100, 8GB memory, 512GB mechanical hard drive, and a Gigabyte motherboard.