When new program is installed most likely information about its location will be added to this section of the registry. If the application's path is changed or if it is removed at all this entry becomes invalid. ARD checks the validity of such references by verifying that all paths exist. Otherwise the entry is considered to be invalid and is going to be removed unless ARD could find some alternative paths.
Uninstall information is required to provide correct removal of software from your PC. ARD checks the validity of references in this section, so that all of them point to existing paths. ARD ensures that all entries from this section point to valid paths, otherwise if no alternative could be found the reference is removed.
Entries in this section contain information about different COM and ActiveX objects registered in the system. ARD checks that all of the registry keys point to existing files. If ARD can't find the file referenced by some registry key then the key is considered to be invalid.
Some applications store information about location of their help files in this registry section. ARD verifies that all of those paths actually exist. If ARD can't find the referenced file it searches all specified local drives for its name.
This section of the registry contains information about all file extensions registered in the system. ARD verifies that registry keys in this section reference applications which correspond to existing file paths.
Fonts section holds file paths of all registered fonts. ARD checks that all entries reference valid files on local drives. If it can't find some file then the reference is considered to be invalid and is removed.
This section contains references to files/folders which were recently used by the user. ARD checks those references for validity and if it finds some invalid link it will delete it from the list.
The section contains references to shared DLLs (Dynamic Link Libraries). DLLs hold functions which can be called by different applications, thus if it was removed then the link becomes invalid and there's no further need in its existence. ARD takes care of such references verifying that all DLLs referenced by the keys of this section exist, otherwise it clears the reference.
This section contains references to shared folders on your computer. Those keys hold settings for the folders on your network. If some shared folder is deleted or removed then the reference becomes invalid, since it doesn't point to the real location of a folder any more. ARD recovers such broken references if it manages to find the folder with the same name on some of your local drives.
Startup sections of the registry contain information about applications and services which are launched each time the system is started. ARD check the validity of the referenced programs to make sure all those paths exist.
ARD also scans all shortcut files (*.lnk, *.pif) checking their validity. If it turns out to be that the shortcut references invalid file or it has invalid icon then ARD tries to find the original object/icon in order to repair the shortcut.
This section contains information about virtual device drivers, which are used by your Windows OS. ARD will scan this section for the validity of specified paths. If it's found that the file doesn't exist the link is considered to be invalid and is either removed or substituted by the correct path if it exists.