Updated bios or updated drivers can cause this.
Nothing that has anything to do with our software. We don't try to do hardware detection ourselves, we only ask to the Esellerate library, which in turn ask to Windows drivers so, if one of your drivers has decided to report a different hardware id, Esellerate would report it and our software will require a activation.
However, Esellerate is able to recognize if your hardware is new or just updated, so it's not certain that, by reactivating, you consumed one of your activation.
In addition to driver or bios changes, this can possibly caused by registry cleaners utilities that cleaned too much, including your activation keys.