Cant turn on computer.

[Midtskogen]

Hey! I have a 990FXA-GD65 motherboard, and a eightcore processor. It's a built computer, and it worked fine a long time,except for the fan speed, which i'm not yet sure how to reduce. But today, when I tried to turn it on, i got a black screen,and the little line in top left corner stopped reappearing, and in the bottom right it said "A3"
Anyone know what this is and how it can be fixed?

 

[gene_11]

u can try to resset the cmos,