Windows 11 PC not starting

[UnKompetent]

I installed w11 yesterday and today a game tolled me that I have to enable secure boot. I wanted to do it but it didn't work. I searched for a solution. A few articles sad that I have to switch from uefi to a other setting I think it was mbr. Now pc is not showing any thing. Rgb is on I can't get into bios and no windows error. I also switched hdmi and dp cable. 

(I'm not sure if I have to include pc parts with a problem like this) 

[Alireza]

you should put your system in UEFI again and disable CSM

plus you should install windows in GPT mode 

if you disable csm

you can enable secure boot

[UnKompetent]

2 hours ago, Alireza said:

you should put your system in UEFI again and disable CSM

plus you should install windows in GPT mode 

if you disable csm

you can enable secure boot

How can I do that without being able to access the bios