Why doesnt my computer start?

skollin1

Honorable
May 11, 2013
128
0
10,680
When I turn on my computer nothing shows up on my screen. The graphics card works and I tested my screen and cable. This happened a few months ago and I just unplugged things and reconnect and it works but there wasnt a clear reason how i got it to work again. I did the same thing again and it worked after a few restarts but when i closed my computer and put it back nothing showed up on the screen again. Could this be my motherboard defective? I have an ASrock 970 extreme 3.