Volume Booster Software for Windows

Is there a software, preferably, freeware, to increase the volume output? Thanks!

Not for Windows, but on linux, you can finetune all the gain stages and the pumps of all audio devices to you liking to make your audio much better. Modern audio chips have digitally controlled voltage, and you can tune the integral opamp stages for performance, but setting the gain stage to a fixed barely non-clipping value to match the amplification, after having boosted the pumps for high voltage operating with more headroom, volume and clarity.You can individually finetune analogue and digital gain for individual channels, and the different voltages at different circuit points.

You can even do that on custom ROM's for Android linux. That's why good custom ROM's make music sound so good. If you have an oscillator at home, you can finetune it to the exact maximum performance your individual hardware can deliver. It's the last 5% of performance that you get out of it, that makes all the difference. A well-tuned smartphone sounds so much better than an external amp just thrown together by someone that doesn't have an oscillator to make the most out of the hardware, because the external amp will still be 5 V fed by the USB port, whereas the smartphone at least will get 7,4 V perfect DC to the audio circuitry, which can be boosted very easily and will stay perfectly clean. It's all about the details and scientific logic instead of marketing myths.