Problem with noise comming from speakers

Hello,
Hi
Can anyone help me with this problem I am having?
I am using a Hercules RMX dj controller attached to my Dell XPS 15z laptop via USB3 lead and the sound output comes from the sound card (part of the DJ controller) to the PC stereo input on my ONKYO 7.1 amplifier with the input set to Direct Audio which drives its front speakers Bi-amped. The problem is there is terrible noises like an old modem sounds and buzzing which reacts especially when you say open a program and the sound of it opening comes through the speakers, this also happens when I load songs into the program I am using via the controller Virtual DJ 7.05b Pro. The midi controller is powered via the USB cable. I find when I disconnect the power lead from the laptop the noises stop but I cant work without the power lead connected. I tried the system on two other sound systems and this does not happen at all. I changed leads and connected to different power outlets but the problem remains, I only use professional standard cables and equipment. I am baffled by this because I dont know if its the laptop, midi controller or the amplifier causing the problem. I would say its an earthing problem but I dont know from where or if there is anything I can do to earth it, apart from the obvious like grounding metal parts of my equipment to earth I dont know what else to do, any help would be appreciated..

Thanks