Sluggish computers can be a real drag on productivity. What's more frustrating than watching a computer struggle to complete what used to be an easy task when then machine was new?

Most computers run slowly not because the hardware has become degraded but because of issues with memory. As users install programs and browse the internet, those files leave traces of themselves behind that aren't completely cleaned up even after deleting cookies and running program uninstallers.

Luckily, there are a host of apps that can easily and quickly boost your PC or Mac's performance by getting rid of unused files and freeing up disk space. Here's a look at five that you might find useful:

1. Revo Uninstaller
After Windows users run the Revo Uninstaller, this app goes back and clears related files and programs that Windows might have missed in its own cleanup process. The app lets users customize their level of uninstallation, from light to deep, and a "hunting" mode that can pinpoint specific tasks and files to eliminate. Read more