Re: Studio XPS 1640 multimedia keys/buttons above keyboard not working.
I found this fix on other forums and it worked for me:
- turn laptop off
- unplug power supply cable
- remove the battery, then replace battery
- plug in the power supply
- hold power button down for 30 seconds
You should see the touch buttons flicker back on either during the 30 seconds or release the button after 30 seconds and then press it again.