Minecraft shader not working - everything is dark?

Hello dear community!

For a long time I have had the problem that all shaders do not work for me with Optifine (in every version). Everything is black and you can hardly see anything except the sky. I have an NVIDIA GeForce GTX 750 Ti. The problem has only been occurring for about a month and I really can't explain it to myself! The problem occurs in single player worlds and on servers. Does anyone know a solution, I haven't found anything on the internet that could help.

Try to reinstall everything and if it does not work then maybe. To install a weaker shader because your PC may no longer be able to do it

* but don't know my way around very well

I'll try the reinstallation. It can't be because of the PC, it did it beforehand.