Question Cannot boot without CSM support ?

[ChichiBambino1]

Im trying to turn on secure boot so that I can update to windows 11 but when I turn off CSM support it shows no boot device on my PC. I have a SATA SSD which has Windows 10 installed on it.
I am fine to delete everything and reinstall Windows but I have no blank DVD or a USB stick.

 

[Lutfij]

Welcome to the forums, newcomer!

I am fine to delete everything and reinstall Windows
If you're going to go ahead with reinstalling the OS, make sure your motherboard is on the latest BIOS version, following that, the BIOS is set to UEFI(CSM disabled), fTPM/TPM enabled and lastly Secure Boot enabled.

Speaking of motherboards, please list the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
include the age of the PSU apart from it's make and model. BIOS version for your motherboard at this moment of time.

but I have no blank DVD or a USB stick
You will need to source a 16GB pen drive in order to create an installer for your OS. Having two at hand would be a good idea since upgrading to Windows 11 using the internal upgrade path in Windows 10 ends up being half baked, meaning you will have to reinstall Windows 11 after the upgrade is completed.

 

[CountMike]

Im trying to turn on secure boot so that I can update to windows 11 but when I turn off CSM support it shows no boot device on my pc. I have a SATA SSD which has windows 10 loaded on to it. I am fine to delete everything and reinstall Windows

Without USB storage of at least 8GB you cant do clean windows installation. only In place upgrade from W10.
Since you obviously didn't install W10 in UEFI mode now you have to convert your disk to GPT first, then you can disable CSM in the BIOS to enable UEFI mode which will enable Secure BOOT and W11 upgrade or clean installation, Actually W10 can also run with GPT and UEFI and Secure BOOT.

View: https://www.youtube.com/watch?v=cuuOWEWGZIQ

 

[SkyNetRising]

Im trying to turn on secure boot so that I can update to windows 11 but when I turn off CSM support it shows no boot device on my pc.

Show screenshot from Disk Management.
(upload to imgur.com and post link)

Your OS drive probably needs to be converted from MBR to GPT for UEFI boot.
Consult video from post #3.