MS will always be monitoring for cracks and disable them once in a while, like a thief in the night, so users are stimulated to purchase their copies to use comfortably. Just a matter of time and this will always be so. The "temporary" cracks won't work for long, and burning bioses practice won't do for all. If shorter, MS is not at all calm to cracks, in time it'll delete them from user's systems via windows.update and service packs. You can sure use cracks but then you'll have to be very careful updating your system.