Hi,
- Are you referring to product id?
- When exactly do you get the error message?
- What is the exact and complete error message that you get?
I would suggest you to contact HP for the product ID:
http://www8.hp.com/us/en/support-drivers.html
http://h30434.www3.hp.com/t5/media/v1/gallerypage/user-id/120573/image-id/12389i84B9A438EAA4E4B5
If you are referring to the product ID, I would suggest you to try the following steps.
a. Right click on the computer icon.
b. Click on properties.
c. You will be able to see product ID under Windows Activation.