We might agonise over operating system start-up times, but it's not the occasional restart that affects your productivity. It's the little delays that add up over time that you should worry about. Take the humble Windows context menu. It can get filled with crud from application installs and if it's not appearing near-instantly when you right-click, it's time to clean it out.
The tool is designed to reveal shell extensions registered with Windows, including the majority of items you see when you right-click.
Once you fire up ShellExView, you shouldn't have much trouble identifying what extensions should stay or go. The app even comes with additional options, including one to mark "suspicious" extensions -- those that have hidden attributes -- which makes it easier to remove malware that might have previously escaped notice.