Just purchased a Dell Inspirion 531 desktop pc from gumtree for £90 with 19" monitor,keyboard,mouse and tower when i plug the 3.5 connection in rear for my pc speakers it only comes out 1 speaker so thought i needed new speakers but remembered when i went round to see the pc the bloke had it connected to the front which ive just done and voila i have speakers working,drivers say everything is working ok so any idea why they dont both work when plugged in rear.