Ask HN: Achieving high security and privacy by daily re-imaging of your system

I'd like to have my system re-imaged every single day (for example, automatically every night, or whenever I shut it down, or just before I travel with it). Why do I want to do this? Because it cleans up the system and instantly gets rid of all malware, junk, and hidden data. By hidden data I mean temp files, URLs, snapshots, and buffers written out by browsers, editors, media players, etc. If you start searching for hidden data, you'll find that there is plenty of private information that is not found by "cleaning" programs like CCleaner. I'm focusing on Windows here but my question can apply to Mac and Linux as well. How to achieve it? I've thought of 4 ways: (1) Carefully create a complete system (OS and applications) on a virgin disk and then run it as a read-only disk. I'm not sure that Windows can be set up like this since it needs to write to the registry and other places. (2) Carefully create a complete system on a virgin disk and image that disk over to your "working" disk whenever you want to refresh your working system. The working disk is writable, so Windows will be OK. (3) Write a script that first wipes your disk and re-installs, one by one, the OS and all your applications from a trusted source (like a DVD or a read-only external drive) by running the actual install programs, and then applies all your settings (i.e., options, preferences, defaults). I already maintain a readme file that documents the settings I use in every app I install, and it is not a huge list in my case. In some apps, settings can be applied only through the GUI so this could be a hassle to set up. (4) Create a VM that has the OS, applications, and settings that you like, and start a fresh instance of this VM whenever you feel the need. In all of these cases, I'm assuming that the user maintains a clean separation between his data and the apps/OS. In my case, all my data lives on a separate volume. (Even data can be untrustworthy--like JPEG images that cause buffer overflow exploits and macros in Word documents--but let's leave that issue aside for this question.) I see pros and cons with each of the methods above. What are your thoughts? Which way would give good security and privacy, but not entail a huge hassle? Is there a commercial or free product that already does this?