How to upgrade node.js on Windows?

I already have Node.js v0.8.0 running on Windows. Can I just run the latest installer to upgrade it to v0.8.4? I am afraid it will break existing third party modules on my machine.

How do I update my nodejs?

Just go to the official Node.js site (nodejs.org), download and execute the installer program. It will take care of everything and with a few clicks of 'Next' you'll get the latest Node.js version running on your machine. Since 2020 it's the recommended way to update NodeJS.

Yes, you just install the latest version. Generally you shouldn't have any compatibility problems if you are already using the same major version (e.g. Version 0.8.x). If you are concerned about changes, you can always check the changelog for each version (link to changelog is on node.js download page at nodejs.org). That should tell you of any big changes (i.e API changes, etc).