I just finished building a system with an Asus Prime X870P WiFi motherboard, Ryzen 7 9850X3D, PNY RTX 5080, and 32GB of DDR5 (2×16GB). All the lights come on, the fans spin, the AIO seems to run, and the keyboard lights up, but there's no splash screen or video output—only a "no input detected" message. The monitor is connected to the graphics card, and I've tried the available ports. The only storage installed is an M.2 drive from my previous PC with Windows 10 on it, although I planned to wipe it and install Windows 11. The motherboard's Q-LED blinks slowly, which the support documentation describes as a general failure to boot, but it doesn't identify a specific CPU, memory, or GPU fault. What should I check next?
3 Answers
A few important things to verify are whether the motherboard BIOS supports that CPU out of the box, whether every motherboard and GPU power connector is attached, and whether the RAM is in the recommended dual-channel slots. Also reseat the graphics card and test each output. Since there’s no onboard video connection involved here, the monitor needs to be connected to the RTX 5080. If it still fails, clear CMOS and try a minimal setup with one RAM stick, the CPU, GPU, and no storage devices connected.
Try moving both memory sticks to the other pair of DIMM slots. Even if the modules are seated correctly, the board may only train or boot with a particular slot arrangement, especially on a first startup.
Don’t assume the existing Windows installation is the cause—an incompatible or uninitialized M.2 drive usually wouldn’t prevent the system from showing the firmware splash screen. Check the motherboard’s CPU and memory compatibility information and confirm the BIOS version supports the processor. DDR5 compatibility can also be finicky, so testing one module at a time in the board’s recommended slot is worthwhile. If the CPU requires a newer BIOS, use the board’s BIOS flashback feature if available, or have the BIOS updated before troubleshooting the operating system.
The power cables, RAM placement, GPU seating, and display connections have all been checked. I also tried every port on the graphics card. The monitor only accepts DisplayPort, but none of the GPU’s DisplayPort outputs produced an image. The Q-LED is still blinking slowly, which the manual describes as a general boot failure rather than a specific component error.