> What can I do?
The license is bound to the MAC adresse of the network interface card of your machine. So changing the harddrive makes it not necessary to get a new license file.
If you still have access to your old drive you should copy the license file (usually license.dat in the licenses subdirectory in the installation folder of Mathcad) from your old drive to the new one. Guess you already installed Mathcad there. When the license manager moans about the missing license, point it to that license file.
If you don't have access to your old drive you have to contact PTC support as the product number you probably used in your first installation is valid only for a limited number of times (1 or 2, depending on the type of the license).
