Black screen with no display signal after enabling Secure Boot in BIOS
Motherboard fails to output display signal or after toggling Secure Boot for Valorant / Windows 11.
Internal desktop parts run on harmless 12V DC voltage and cannot shock you. Simply unplug the wall power cable first, then touch the unpainted metal case frame to ground static electricity.
Common Symptoms & Tells
- No display signal immediately after enabling Secure Boot or changing PK keys in
- PC turns on, fans spin, but monitor says 'No Signal'
- UEFI GOP driver incompatible with CSM disabled
Interactive Fix Checklist
0 of 4 steps completedSafety isolation and power discharge
Shut down the PC, switch off the power supply rocker switch (O), and unplug the AC power cord from the wall. Press and hold the chassis power button for 5 seconds while unplugged to drain all residual capacitor energy before touching any internal hardware.
Clear CMOS to force motherboard back to default CSM settings
Turn off power supply and unplug PC power cord. Locate the round silver CR2032 battery on motherboard. use a non-conductive plastic pry tool or fingernail (or carefully with a flathead screwdriver without scratching motherboard traces) to release the battery retention clip. Wait 5 minutes. Reinsert battery and turn PC on.
Update GPU UEFI Firmware / GOP driver
Older GPUs (Nvidia GTX 900/1000 series) lack modern UEFI GOP firmware and black-screen when CSM is disabled. Download the official 'NVIDIA Graphics Firmware Update Tool for 1.3 and 1.4 Displays' in Windows.
Convert MBR drive to GPT before disabling CSM
If your Windows drive is formatted as legacy MBR, disabling CSM makes the drive unbootable. In Windows Command Prompt (Admin), run 'mbr2gpt /validate /allowFullOS' then 'mbr2gpt /convert /allowFullOS'.
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