ASIO 4 All is a driver that sits on top of the existing Windows drivers and emulates the ASIO interface. Some additional latency will be added during playback so you will not be able to play as many tracks as you can using straight ASIO. Download from www.ASIO4All.com.
Because ASIO4All sits on top of the existing sound card drivers, ASIO4All will route audio based on it's settings in the ASIO4All System Tray application. In some cases ASIO4All will try to direct audio to a digital or SPDIF output and if you are expecting to hear audio through the analog outputs, no sound will be heard.
To resolve this routing issue, after running SFX and setting up your ASIO patch, an icon will appear in your System Tray (by the clock) called ASIO4All, click on it and open up the ASIO4All control panel.
The panel will list out all the WDM Devices on your computer. Verify that the sound is going to the correct WDM device.
In the above image, ASIO4All will route sound the the HD Audio SPDIF out. Turn off the outputs you don't want sound to go to, and turn on the output that you do want sound to go to.