I uninstalled my previous version of node.js (0.8.11) and downloaded the latest, 0.10.24 from the node.js website and installed it. However, after running
Uninstall from Programs & Features with the uninstaller.
Reboot (or you probably can get away with killing all node-related processes from Task Manager).
Look for these folders and remove them (and their contents) if any still exist. Depending on the version you installed, UAC settings, and CPU architecture, these may or may not exist:
C:\Program Files (x86)\Nodejs
%PATH% environment variable to ensure no references to
If it's still not uninstalled, type
where node at the command prompt and you'll see where it resides -- delete that (and probably the parent directory) too.
Reboot, for good measure.