I just built my first PC and it initially powered on normally. I entered the BIOS, but it wasn't detecting my boot drive, so I enabled CSM in the advanced BIOS settings. After saving with F10 and pressing F8, the display went blank. I restarted using the power button, and on the next startup I tried entering the BIOS again. The fans briefly sped up, a small motherboard LED cycled through three colors, and then the fans slowed down, but I still get no image. The motherboard is an ASUS TUF AMD B850-E WiFi, and I'm trying to boot from a USB flash drive. What should I try next?
3 Answers
The LED color sequence may be the board checking different hardware during POST, so consult the motherboard manual for what those colors indicate. If clearing CMOS doesn’t restore video, check the monitor cable, make sure the display is connected to the graphics card rather than the motherboard when appropriate, and reseat the RAM and graphics card.
Clear the CMOS to restore the default BIOS settings. Turn off the PC, switch off and unplug the power supply, then use the motherboard’s clear-CMOS button or jumper according to the manual. If neither is available, remove the coin-cell battery for several minutes, reinstall it, and try booting again.
CSM usually needs to remain disabled for Windows 10 or 11 and modern UEFI boot media. After resetting the BIOS, check whether the USB drive appears in the boot menu and select it as the boot device. Also reseat the drive and verify its connection if it still isn’t detected.
Since the boot device is a USB flash drive, try another USB port as well. A rear motherboard port is generally the best choice during installation.