In light of the coming GPLv3, here is a quick reminder of what the 4 Freedoms are:
Freedom No. 0 is to run the program as you like (the most basic freedom a program can have).
Freedom No. 1 is to get access and study the full source-code (hence look under the hood).
Freedom No. 2 is to modify the code as you like.
Freedom No. 3 is to spread (copy) the original or modified version to anyone under the same terms as you received the original program.
As one can see Freedom No. 0 is granted by most programs.
To give you a negative example, Microshit Vista Home is not being allowed to run as a virtual machine and therefore doesn’t even have full Freedom 0!