This post is for people who are having a very specific issue.
Please see this before you try this fix. The issue this fix addresses was on an HP Compaq 515 running on Windows 7 Home Premium.
I have laptop with working speakers. When headphones are plugged in, they are detected but do not play music. You cannot set the headphones as the default playback device even if you disable the speakers. Reinstalling the audio drivers does not work
-Open "Add or Remove Programs"
-Uninstall IDT Audio
If this solution doesn't work for you and you would like to undo it, please use System Restore
You could apply this method (basically of making Windows use default drivers) to similar audio issues, ie I have done this with a computer with Realtek audio as well (although the original problem was totally different)