WindowsUpdate drivers are often well out of date.
You probably have the C-Media 8738 chipset (it's used by a lot of manufacturers both for onboard sound and in PCI form at remarkably low prices), which I used for several years on an Elite motherboard.
It produces remarkably good sound quality and although I now use a SoundBlaster Live! the difference is not all that substantial with my IBM 2.1 speakers.
The C-Media website is at:
It's well worth downloading the helicopter 3D surround sound and vision demo file and using it in 2.1 form - it's quite amazingly realistic (I presume it's still available).