Creo does not detect license file valid

As a college student I downloaded Creo 6.0. But after I wanted to open the "setup.exe" nothing happened. Not even after disabling both of the firewall and antivirus. However from an another PC I managed to copy the necessary files to my own. I have the license the use it as a student. I copied the "license.dat" file to the right destination ("C:\ProgramData\PTC\Licensing") but still Creo cannot detect the file.

What should I do in order to Creo detect my license?

Thank you for your forwarding help!