On the heels of yesterday, the same technique that swapped hosts files can be adapted to toggle registry settings too. The registry, if you’re not familiar, is a central database that stores Windows configuration settings.
Perhaps you want to be able to toggle your screen saver timeout from the default of 1500 to a value of 9999. That way, you can easily choose between the screen saver interrupting you or not. I run into a problem when running certain emulators with the screen saver timing out on me; this would solve the problem.
