RE: Dell INSPIRON 15 TOUCH SCREEN NOT WORKING?
What is the exact system model? What is the current OS installed on the system?
Update the BIOS - http://dell.to/1n3X2po - enter the service tag and download the BIOS, update and restart the machine and check. Also, check if there is a firmware available and install the same on the system and check.
Restart the system and press f2 on startup to enter BIOS and check if the touchscreen works in BIOS.
Restart the system and press f12 key on startup - choose diagnostics. Let it run the diags and if you encounter any errors - make a note of the complete error and report the same to us. These are onboard diagnostics and they might possible pick some error if the hardware is not functional.
Also, please click my DELL-username and write me a private conversation with the service tag and your contact details(Name and Email) for case records.
Let us know if you have any other queries.