When I look to boost my sound I tend to buy an external device that connects to the audio out of the computer and have that be the driver for the sound to be louder and richer sound. If the sound chip/driver combination isn't of a high enough quality then I'd install a sound card that will produce a higher quality sound output and then connect that to a quality sound system that takes an auxiliary input. No worries of damaging the computer this way or dealing with driver insanity if going with a name brand sound card that has drivers for the version of Windows your running.
If looking to make it really loud and sound rich, high end guitar amps work awesome which have aux inputs. Just be sure to lower the volume knob on the amp or else you might send yourself an others around you through the ceiling when the computer makes a sound when unexpected of it to be making that sound. I use to connect my Roland 80 watt Amp to my computer when not using it for playing guitar and that was LOUD! It also had a booster button on it that make it even louder than standard setting.
Here is the amp I have connected to my computer.
https://www.roland.com/global/products/cube-80gx/
