Just built a pc for my nephew out of old parts, nothing fancy:
Pentium D 2.8 4gb ram HD4550 1gb XP Professional
Currently sorting out drivers and software; it is plugged into a tv via hdmi. I intend to connect the pc to vga monitor and jack speakers, but sound will only go through the hdmi at the moment. Sound settings in control panel say "amd hd audio rear output", and I cannot see any way of forcing the audio through the motherboard jack instead. Does anybody know how to change the output?
More abouthdmi jack issue
What motherboard do you have?
Control panel, then to hardware and sound, then sound. You should see something called manage audio devices. Plug in your cable and see if it's detected. If it's not detected its either a driver issue or a faulty jack.