Since moving house can't get sound from PC speakers

I suppose that you have plugged the green plug of the speakers in the green socket from the mainboard, in the back. And , of course, the speakers are still functional - try them with any other device that has a 3.5 mm plug.
Probably the audio setup was disturbed: unplug the speakers from the pc, reboot, plug in the speakers - the Audio Manager (the one that controls what and where is plugged) should open to ask you what has been plugged. If it doesn't do that unplug the speakers again and open it manually. If when you plug the speakers it doesn't sense that then the audio driver is busted - reinstall it.