I have a custom built PC that was running perfectly fine. But then i accidentally bumped it and it shut off and now it wont turn back on. It powers up, but it wont POST or do anything. the HDD light stays on. i have tried clearing CMOS, reseating RAM, Video Card, and unplugging my HDD. Nothing worked in fixing it. Does anybody have an idea as to what happened when it got bumped and if i can fix this without buying something else or sending it into a shop?