Hello Meats.
I understand you are receiving problems with your Photosmart C4780. Since this is a forum based community we try to respond as soon as we can. I apologize if you have been waiting a while for a response.
Have you performed these troubleshooting steps from this HP document: The Touch Screen Does Not Respond.
If you have followed this entire document please let me know so I can continue to assist you.
Looking forward to hear from you.