computer troubleshooting

I was in my brother's pc's bios trying to turn on secure boot because Valorant required it, In the process I created a public key, enabled secure boot and clicked save and exit. When it restarted it had no display but the fans were spinning. This pc has worked perfectly fine for almost a year...

Okay I am getting this problem for like 5-6 days now . I have some common games that I play that runs good on my Mid end PC like ARMA 3, Battlefield V and CSGO But for the last few days Every game seems to run really badly like ARMA 3 is getting weird FPS Drops from 40 to 3-4 I know ARMA 3 is...

After cleaning with a microfiber cloth, I put my PC back expecting it to work once again, especially since previously the computer was outputting sound and video flawlessly. Now my computer will not output any video (perhaps sound) even when I changed the monitor, from DVI-I, to HDMI, to HDMI...