It is not permissible to make copies of disks without the permission of their authors, because of copyright. This is a valid right and it is not permissible to transgress it, in accordance with the conditions drawn up by both parties.
It says in the fatwas of the Standing Committee for Issuing Fatwas, led by Shaykh ‘Abd al-‘Azeez ibn Baaz: It is not permissible to make copies of programs for which the authors have not allowed copying, except with their permission, because the Prophet (peace and blessings of Allaah be upon him) said: “Muslims are bound by their conditions.” And he (peace and blessings of Allaah be upon him) said: “A Muslims’ wealth is not permissible unless he gives it willingly.” And he (peace and blessings of Allaah be upon him) said: “Whoever reaches a permissible thing first, he has more right to it.” This applies whether the author of this program is a Muslim or a kaafir who is not in a state of war with the Muslims, because the rights of a kaafir who is not in state of war with the Muslims are to be respected like the rights of a Muslim. And Allaah knows best. End quote from Fataawa al-Lajnah al-Daa’imah.
Shaykh Muhammad ibn Saalih al-‘Uthaymeen (may Allaah have mercy on him) said the following with regard to this matter:
This is to be based on what is known practice (al-‘urf). If a person wants to make a copy for himself and the original author of the program did not state that it is not allowed to make copies for personal or public use, then I hope that there is nothing wrong with it, but if the original author of the program stated that it is not allowed to make copies for personal or public use, then it is not permitted at all. End quote.
Based on that, it is not permissible to copy the disks for operating systems etc, so long as the author has not given permission for that.
But if these disks belong to a company in a state that is at war against the Muslims, there is nothing wrong with copying them.
And Allaah knows best.