There was also software (probably still is) that records the state of your computer before using a program. Then you'd run the program and it recorded any changes (with filters, of course), which you were able to undo with a simple button press. At the time, it was usually a change to some registry entry. This was another method I used to reset timers and usage limits of software like the one you mentioned. As before, I tracked down registry changes by hand until I discovered a more convenient option. This was necessary, because many programs with usage limits left information behind when uninstalled so that you couldn't just do what you did.