When you start SizeMeNow for the first time, it looks at any drives that it can find on your computer and adds them to this view so they can be scanned. You can add and remove items from it, as well as run the automatic drive finder again, by clicking the "Manage Drives" button on the main toolbar to open the Drive Manager.
Note that the larger the item you click, the longer it will take to scan. For example, scanning a C: drive will take a much longer time than scanning a folder with just a few files in it, because SizeMeNow will have to go through all the subfolders and files in the entire C: drive to generate its reports properly. However, you can cancel the scan at any time either by choosing Edit->Stop Scan menu item or by clicking the red "Stop" button on the main toolbar.
(c) 2008 Ketara Software