It's possibly the usb ports. Anything with its own power plug into the back ports. Anything requiring power plug into the top ports. The back ports have less power than the top ports so i plug the mouse, ups and printer into the back and my hub into the top which powers my external h/d and lighted k/b. Since doing this I have a solid blue light. Have also read that using the back hub for a device that draws to much power will cause a possible fan case issue. I was getting a warning from the m/b diagnostics before rerouting everything have had none since . Hope this helps .