Maximum Windows volume, laptop's bar is at 50% - how can I boost the system volume further?

I have a laptop with Windows 7. I set all the usual volume control are at max (via the mixer), but there is a separate (hardware?) volume bar that is displayed whenever I change the volume, and it is at 50%.

Is there something I'm missing? How can I increase the volume further?

Edit - The model is Lenovo Edge, I'm not sure of the exact model, the label on the bottom says "Type: 0217-22G".

Edit2 - More than fixing the display, what I'm really looking for is a way to arbitrarily boost the volume beyond the max. Why should there be a software imposed max in the first place (well, usability is one reason, but some Youtube videos have really low volume)?

Solution 1:

The Lenovo Community Forums have a thread recommending you uninstall the Realtek driver and use the generic Windows 7 driver.