This tool is capable of analyzing all the drives connected to your PC, so you can check all your hard disks as well as your externals.
The interface is very straightforward and easy-to-use for those inexperienced in working with partitioned disks. In the interface you'll see all the drives connected to your computer that are ready to be scanned.
Once you've started the process, you'll see the total number of files scanned and space they occupy on your system. Doing these tasks every once in a while will improve the performance and speed of your PC, which is inevitably affected as time goes by.