I have an older laptop running Windows 7 Home Premium and have wiped the hard drive clean. I re-installed Movie Studio HD 11 and it ran fine until the trial period ended. It now says I need to register it and obtain a Authentication code. I have a hard copy CD that I purchased that has a serial number and authentication code on it but that does not work. I went on Magix site and entered the serial# to get authentication and it says it needs to be registered. But when I try to register it Magix says that serial number has already been registered. Can anyone help?