a constant beep infact lol I tried to pull out the one stick of ram whilst a machine was still running for some reason the beep came from the surround sound speakers that were hooked up and they were pretty loud oviously had flicked the dial on the subwoofer next to the pc whilst dragging it out but anyway long story short computer crashed I shat myself leaped up hit my head on the table put it back in and the pc worked fine