This is the software publisher's description.

Windows is famous for getting more sluggish the more you use it. One reason for this is that many programs leave your computer full of digital garbage when you remove them. Every time you try out a new program and then uninstall it your system gets more and more clogged up with redundant program components that just get in the way and slow things down.

Ashampoo Uninstaller 4 completely eliminates this problem. It lets you test software with confidence because you can be sure that no trace of programs you remove are left anywhere on your system. It does this by comparing compact “Before” and “After” snapshots that identify exactly where all program components and settings are located. Uninstalling is completely safe, with automatic backups and a special Reinstaller for quickly reinstalling programs with all their settings.

In addition to uninstalling, you can also use UnInstaller’s comprehensive “Before and After” comparisons to monitor and identify the secret activities of any program – for example hidden files and Registry keys. Just take a snapshot, run the application that you want to monitor and then take another snapshot. UnInstaller then compares the snapshots and shows you all the changes the program has made anywhere on your system.