In Windows XP there were always backups form the Windows Updates in a hidden directory in the %SystemRoot% folder (usually C:\Windows). This hidden directory is named after the Knowledge Base article for the relevant hotfix, such as $NtUninstallKB867282$, and contains an uninstallation utility. Some of them where fairly large. Especially the service packs that where as large as 500Meg. There were a lot of utilities to remove these hidden folders without removing the hotfix. For example, http://www.dougknox.com/xp/utils/xp_hotfix_backup.htm
At this time I am just very curious because in Windows 7 I don't see the hidden folders. Are they no longer kept, or are they just in a different place? I get a little freaked out because of the many Windows Defender updates that I receive. As I continue to use Windows 7, I want to know if I can manage any wasted hard drive space.
These files are stored in %SystemRoot%\SoftwareDistribution\Download. You'll need to stop the Update service to delete them. Have a look at this link for more suggestions about removing redundant files.
Presently removing Windows Update Backups using TuneUp Utilities 2010 but I note in my 64bit Windows 7 Accessories/Disc Clean Up there is an option to remove the old Update BackUps! Bit cautious myself but has anyone tried this?