Now is the last part. You'll need a Phillips 00 bit for this, as you must remove two screws to "free" the PCB.

Once unscrewed, you *don't* need to remove the board, but just try to gently pull it up along the upper-side (nearer the headband) to re-align the volume slider back into position. Slide the volume knob after every tug upwards and see if it's re-aligned.

You shouldn't need to remove the PCB, and you probably won't want to, as re-attaching it means you have to re-align the volume slider, hardware mute button, 3.5mm jack AND the two USB ports. While it is doable, it is not necessary for this specific technique.

Once the slider starts running smoothly back and forth again, this usually means the slider has re-aligned its center axis back to the volume control unit. Re-attach the screws and the upper plate with the cups, and try connecting it to your PC and check if it's working again.