Mac screen displays briefly before going black.

My Mac has developed the following problem:

When I boot first time in the morning it boots, I can enter my username and password and to the desktop screen. It then works briefly before you hear a brief ‘snick’ noise and then the display goes black.

From my other Mac I can share the screen etc and it works fine.

After a period of time I can move the mouse and the display comes on but it does exactly the same.

I have tried it without any peripherals but I still have it.

Could the hot weather be causing it as the fan seems to be running quickly. The other thing I thought is that I only have 8GB of RAM and do a lot of photo-editing, would upgrading to 16GB or 32GB solve the problem?

I would be grateful for any ideas or advice.