What is the ruling on money earned online using a device (computer or phone) purchased with money from an unlawful salary, knowing that the computer's operating system (Windows) is not genuine, and the intention is to purchase an original copy later?

You are required to return the salaries you received without entitlement. If that is not possible, then you should give them to the poor and needy. There is no objection to benefiting from money earned online if the work itself is permissible. Using a non-original copy of software necessitates guaranteeing the benefits that the software owners missed out on, and this value is to be estimated by experts and specialists.