Troubleshooting My Computer’s Peculiar Startup Issues

Recently, I’ve noticed my computer behaving quite strangely—though “strange” might be an understatement. To provide some background, about three years ago, my machine underwent repairs after being fitted with a counterfeit part from an unnamed source. Following that repair, I’ve dealt with several quirks. Initially, I started encountering a persistent “CPU fan error” message during startup. Oddly enough, the fan was operational, and the CPU temperature was within normal ranges. Rather than reaching out to the repair service for help, I ended up relying on the BIOS to bypass the issue. In hindsight, a call to the technicians would have been wiser, but here we are.

Eventually, my Windows installation began to fail, leading me to identify a problematic SSD, which I’ve since replaced. That seemed to resolve things for a time. However, I now find myself facing a new challenge.

Currently, pressing the power button on my computer results in inconsistent behavior; sometimes it powers up, while other times it doesn’t. When it fails to start, the power button illuminates, the power supply shows signs of activity, and all components appear to be operational upon inspection. Yet, I receive no response from my keyboard or mouse, and nothing displays on my screen.

On the occasions when the computer doesn’t turn on, I often find myself stuck in a loop of switching it off and on repeatedly, toggling the power supply, and sometimes even opening the case to double-check connections. Strangely, everything seems to be properly connected during these inspections.

Besides these startup frustrations, the computer otherwise functions normally. However, I do encounter other hiccups; for instance, switching the HDMI connection between my monitor and TV sometimes triggers a complete system restart. Additionally, if my leg accidentally nudges the computer while I’m getting up, it can abruptly shut off, and on rare occasions, it powers down arbitrarily.

I would greatly appreciate any guidance or suggestions from fellow tech enthusiasts who may have experienced similar issues. Thank you for your support!

For more context, I’ve included some images and videos demonstrating the issues I’m facing: View here.