Windows XP folder contains many folders with names like $NtUninstallKB842773$ [duplicate]

This folder contains data that is necessary if a hotfix needs to be removed - in this case, KB842773. The light yellow folder indicates that they are normally hidden. While you can safely delete them, if you do so, you will not be able to uninstall the hotfix in question. The folder name $NtUninstallKBxxxxxx$ refers to the Microsoft Knowledge Base item at http://support.microsoft.com/kb/xxxxxx (replace the xxxxxx with the actual number). The folder name may be blue; if it is, the folder and its contents are compressed with NTFS compression to save disk space.