Sound does not work with devices.

Question

i have an acer Aspire 5570-4011 with windows vista...it has 3 plugs in the front from speaker attachments and headphones....the sound works fine when nothing is pluged in but once i plug in my head phones or speakers the sound no longer works, ive been told i may have to re-down load the driver and i have no idea how to do that...what do i do