Ok, thanks for the feedback. Still can't tell what your problem is, so got another test for you to try. This is an updated version of the HPL Sound Test published a couple months ago. It uses the game engine, so we can make a better idea of what's going on if it works. Again, same procedure: run it and post the hpl.log file. Note that this time the log will be generated in the same folder where the program is.
By the way, sorry for the delay, had some problems uploading the file
Get the test
here (megaupload)