Igpu giving display but dedicated GPU isn't

[bug]

I bought the PSU around 5 months ago. I don't think I took out the cmos battery after updating the bios, but that was like 6–7 months ago. Furthermore, I recently gave the mobo and cpu to my friend, It was working without any issues then.

You can also go for the basic troubleshooting: install mobo, add CPU, one stick of RAM, see if you get video. Add the GPU, see if you still have it. Just take everything else out of the equation. There's some sort of conflict somewhere. Something is different between the system that used to work and the current one.