Seeing as Speccy and not likely much of any other system info tool will show the actual manufacturer of the motherboard likely due to using generic drivers due to its age), look at the motherboard and locate who actually made it. The chipset used was used by most if not all motherboard manufacturers as the time. The chipset itself did include Via audio,
but not all motherboard manufacturers would have used it, and may have opted for one of the other onboard audio solutions from the time (most if not all AC'97). Once you know who made the motherboard then visit their site and get the last XP driver for it, as there likely won't be anything for Windows 7 (or Vista for that matter) for it due to its age.
My Computer
At a glance
Win 7 Ultimate x64FX-8350 @ 4.6 GHz so farADATA XPG V1 Series Black 8GB DDR3 1600Sapphire R9 270x Dual-X