Hello. Download and install a fresh copy of the Realtek audio driver. If doing that doesn't fix the problem, switch to the windows native audio driver.
1. Open the Device Manager (find it in the Control Panel, or type devmgmt.msc into the search box). 2. Expand the "Sound, video & game controllers" and right click on "Realtek High Definition Audio". 3. Select to "Update Driver Software". 4. Click on "Browse my computer for driver software". 5. Click "Let me pick from a list of drivers on my computer". 6. Put a check in the box "Show compatible hardware" if not already checked . 7. In the list of devices, click "High Definition Audio" (the native driver). 8. Click "Next". 9. On the Update Driver Warning box, click "Yes" (install the driver). 10. Restart the laptop if prompted. If not prompted, sometimes you have to restart, sometimes not. [To get back to the Realtek driver, do it again but reverse the names in steps 2 and 7.]
If the headphones still don't work after doing that, it is because of hardware failure.
Jim Coates -- 15 years on the Dell Laptop Audio boards -- since 2/6/04