Let's think this through.
Do you really think an attacker from the internet has the time or
inclination to read through your registry and mess it up? Why bother,
when with a single worm or rootkit they can destroy thousands of computers?
And what would be the point of vandalizing your registry? Nobody does
that anymore. Now the name of the game is making a profit. No money is
made by messing up your registry.
In short...an attacker on the internet doesn't give a da*n about your
registry. And if you have a correctly configured firewall, no one from
the internet even knows that there's a computer at your IP address.
It's a different story if you actually know someone who a) has a desire
to make your life miserable and b) has a sufficient command of
technology to know how to break into your registry from a remote connection.
Moreover...and take this from a former all-star noob computer
destroyer...if you understood enough about the internals of the Windows
operating system, you wouldn't be asking your question. Do you really
want to mess around in something you don't understand?