hdarun.exe is for use with hda2.dll.
This program keeps the hda2.dll wave buffers active.

When Enhanced mode is active this program is not needed. 
It is needed when windows is in standard mode (win/s).

The mmtimer parameter will activate a timer upon form activation.
The loop parameter will activate looping upon the first message.

Examples:
hdarun.exe mmtimer
hdarun.exe loop
hdarun.exe mmtimer loop

You could add hdarun.exe to the progman StartUp group.

If you don't like the way it looks you can try:
hdarun.exe hiddenloop
