It is permissible for the one who owns the operating system to put it on any computer he wants, and he does not have to adhere to the conditions, because the condition is contrary to the contract of sale and purchase. The valid contract of purchase comprises the transfer of the sold item to the purchaser and the transfer of the price to the seller. Once the purchaser has taken possession of the sold item, it is permissible for him to dispose of it by altering, changing, developing and putting it in any place he wants, because that is a permissible way of disposing of his property.
And Allah knows best.
Reproduced from Islam QA