The Enterprise edition offers all the features of SpaceObServer while the Standard edition is limited in some points.
With the Standard edition you can scan only one server, Exchange Server scans are not available and the OLE Automation interface is not included.
Please find a detailed comparison of both editions here.
Unfortunately there is no short and easy answer to this question because usually one cannot know where a file came from and what it is used for. Generally temporary files and cache files of the internet browsers can nearly always be deleted safely. Besides deleting files, the File Search of the software offers you to move files to a different drive or to a compressed ZIP file (preserving the file system hierarchy) which can then be archived. That way files that are still needed can be easily restored, either manually or by using the restore script that the software is able to generate optionally.
We do not work with activation codes because you can find them very easily on the internet. Typically software manufacturers protect against this problem using online activation, but this would make customer dependent on the availability of our activation servers and an internet connection.
We are working with separate trial and full versions instead, where the full version is not freely available for download and must be installed over the trial version. After purchasing our software, customers get an account for our customer area where they can download the full version for at least 12 months. Our customers will also receive a personalized installation key, with which they can install the full version. Login data and key should be stored in a safe place. Installing the full version over the trial version will preserve your existing data and settings.