System starts when removing / inserting USB device

Bit of a strange one here:

System is shut down completely.

Remove or insert device into USB port & system powers up!!

Happens with both ext hard drive & printer so guessing it's not the USB device.

Tried so far :- Updated BIOS & disabled USB 2.0 in BIOS, also disabled Boot from external device in BIOS.

Worked with PCs for some years now & never seen anything like this before.

Any help much appreciated, born2bl8

is it the same on different USB ports and with non powered USB devices? definitely strange though - could be a short on the individual USB port or on the USB controller ...

You have "Wake on USB" enabled in your bios settings.

Check you motherboard manual on how to disable.