I see you have a Dimension 5150. I have a Dimension E510 which is identical (the 5150 was sold in the US only as the E510). I also have an Audigy SE sound card installed and it has the What You Hear but it has Vista Home 32 bit OS, not Win 7.
I went through this about a year and a half ago researching this for a client. At the time, SoundBlaster had several versions of the drivers
listed. An older driver
had the What You Hear but the newer driver did not. I haven't looked at the Creative downloads for the Audigy SE but if there are several versions, try an older Vista compatible version and see if it gives you the What You Hear.
I have no idea why Creative removed that function. I'll start up the E510 and see if I can determine the version and post back.
I have an HT Omega "Striker 7" PCI sound card installed in my main PC and it has the System Mixer function (what SoundBlaster calls "what you hear"). It is fully Win 7 compatible.