Installed Civil 3D 2013 on a laptop (windows 7) using the 30 day trial version and that worked fine, but the days ran out, so then as I had planned to, I've tried activating by using our companies serial # and product key that are in good standing. But I get an error message that the serial # is not valid for product I'm trying to activate - error 123. I'm guessing this has something to do with starting out with a 30 day trial.
Hi matthew0815 - The serial number that you are trying to use is linked to a networked license of Civil 3D 2013, which would explain the inability to activate as a standalone.
There is a registry edit, documented here, to change the deployment type for AutoCAD 2013 products, or you could simply uninstall and reinstall as a networked license.
Please let us know if you have additional questions and or accept this response as a solution f it fully answers your inquiry.