The same sound card may have different drivers, and some of them can have the Stereo Mix / Wave-Out mix, while it won't be available in other drivers. You may need to try different drivers to find out which one will work for you:

• From the manufacturer of your computer (Dell, HP, Sony, Acer, Asus, Toshiba, Lenovo, LG, Samsung,...)
• From the manufacturer of your sound card (Intel, Creative...)
• From the designer of your sound card (RealTek, Sigmatel,...)

You can also try to use a sound card driver from another manufacturer (for example, an LG driver for an Acer laptop), but make sure the driver is made for exactly the same sound card and the same Windows version that you have!

You can try different drivers, but make sure that a sound card driver is compatible with your hardware. Otherwise you can damage it!