O

Objects executed at the operating system startup - A set of programs required for launching and correct operation of the operating system and other programs installed on your computer. Your operating system runs these objects during each startup. Some viruses infect startup objects and can prevent the operating system from loading.
OLE object - An object linked or embedded into another file. Kaspersky Anti-Virus scans such objects for viruses. For example, a Microsoft Excel spreadsheet embedded in a Microsoft Word document will be scanned by Kaspersky Anti-Virus as an OLE object.
On-demand scan - A mode of application operation initiated by the user that performa a scan of files of all types resident on your computer.