I recently just built a new AMD Ryzen 3900x gaming PC and I moved my tower to a new location. Everything had been working for days and after moving, I reconnected everything and turned it on. The computer made a “beep” noise, but wouldn’t go into the post screen.
Naturally, my first instinct was to freak out. Had the motherboard, CPU or power supply died? Maybe I got a dud board?
The debug LCD display inside was showing a code of 99. If you Google what a bios error code of 99 is, you get a wide range of probably causes for this error. It’s a code that is telling you that the computer is having a problem booting (well, thanks for stating the obvious).
The code 99 is not technically an error code. It’s just showing you at what point of the boot process your computer is at. It just so happens if the computer doesn’t go beyond 99, it’s having an issue booting.
After I accepted the fact my new board might be a dud, I decided to try the tried and tested debug process, disconnecting every USB device. Well, that worked.
Slowly, I started plugging everything back into my PC and it continued to work. After some investigation, it turns out my Nintendo Switch Pro Controller was the culprit. I have no idea why my Switch controller was stopping my PC booting, but disconnecting the cable fixed it.
Funnily enough, I only had my controller plugged in to charge. I usually use my controller via Bluetooth. So, if you encounter this issue, don’t freak out, disconnect every USB device and see if that helps.