I believe that if you put in all zeros for the serial number then the product key will gray out and you will be able to install.
Keith is correct. You will have to put in 000-00000000. Are you still having issues with it? Let us know so we may assist you.
I have downloaded the free version of Civil 3D 2012. Entering all zeros for the serial number has not worked for me. It says this serial number is not valid. I made sure i checked the free trial version during the installation. Any help for this?
You shouldn't have to add any serial numbers when running a trial version of the software. All you have to do is choose try on the activation screen. Please look at the attached screen shot to see where you have to click. Please let me know if this works for you.
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