Which is technically illegal if you don't own a retail copy (the copies that come pre-installed are OEM copies). Retail = 3 activations; 1 active machine at a time, but you CAN transfer the license to another computer as long as the old computer does not have it installed at the same time. OEM, however = 1 PC, and is non-transferable (legally that is; it can still be done how SOULphire is explaining, but does not negate the fact its against the EULA).