Hello, i been working on a custom pc for a while now and i finally got the last peice which was the RAM. after i plugged it in and made sure everything was connected i turned on the power supply and pressed the "on" botton on the chassis and nothing happend ? my motherboard has a yellow light on but it doesn't turn on. my friend said that it could be because of the jumpers but i made sure they are all connected properly. what should i do ? Thanks !