Thanks for posting. I’d be happy to help with your adapter!
Our adapter will pass the audio signal if present from the DisplayPort output of your Dell. Some early versions of DisplayPort did not support sending audio signals. I looked at the specifications for your system here -> http://www.dell.com/downloads/global/… on page 22 and Dell does not specifically state whether the DisplayPort output can carry an audio signal.
Continuing to look at the document, the system has an Intel Q45 Express Chipset, with integrated Intel GMA 4500 graphics. A quick search online shows others having a similar issue with audio not passing over DisplayPort with similar system specs (for example here -> https://community.spiceworks.com/topi…)
Taking a cue from that post, if after updating the BIOS to the latest revision, ensuring the latest Intel graphics drivers are loaded (which would provide for the audio driver), and checking that the default playback device is set correctly in Windows the audio does not still not pass we can assume that the DisplayPort output on this system does not support passing audio (you may wish to ask Dell to confirm). If that is the case we certainly don’t want you stuck with a product you can’t use, and we offer a 30-day no-hassle return policy via the automated system at amazon.com/returns.
Let us know if that information helps and we’ll go from there.