Pc starts up but no display

Good day

Theres alot of posts about this but nothing that helps me.
My pc power light(green) goes on aswell
As the dvd drive light then goes off.
Theres another light with a picture of a light next
To the power button which use to go on but now doesnt.
Sometimes it works but mostly not.
I tried the ram and all fans work aswell,tried the
Graphics card aswell. I replaces thermal past.
Pc also freezes randomly when watching any
Movie
When the pc goes on it runs fine while playing games
There is a green light next to 1 ram slot on mb and when I switch on the pc the green light stays on but a red light also appears.
I bought new ram aswell and a new psu.

I really hope some1 can help as this is getting
Anoying