I just built my first pc. At idle it doesnt make any sounds, but as soon as I launch a game, I can hear a rattling noise from the case, and as soon as I close the game it stops. I tested all the fans and none of them made any rattling sounds, then I took the PSU out of the case and tried again. The sound clearly comes from the PSU. The PSU fan isn`t spinning so I don`t know what causes the sound. I also tried the PSU both ways, but it didnt make any difference. (PSU is Cooler master Masterwatt 550)