I recently purchased a corsair cx550m refurbished from amazon (I had to use amazon instead of newegg because of a gift card) and when I plug in everything, the motherboard doesn't get power. I was getting frustrated with this problem after trying many different tests to make sure something else wasn't short circuited, but it turns out that I have to bump the power supply in order for it to start working. It only happens when you plug in the power supply from the wall to turn on the mobo's led, but after that It works flawlessly. Why does it need to be bumped to get power to the motherboard and how can I fix it / return it if I can?