File Extension LNK
File extension LNK is most commonly used by LiNK files on Windows operating system. These files are also known as "shortcuts". These files are used for quickly accessing some resource: program, document, website, etc. These files contain information about the location of resource shortcut links to (ex: http://www.yahoo.com, or c:\users\John\Documents\Thesis.docx). LNK files also contain and "icon" - small image to display on the desktop or in the start menu that helps distinguish shortcuts from one another.
If LNK file references an executable it contains additional data specific to executable files such as directory to run program from, initial window size (maximized, minimized or normal) and several tweaks and knobs related to compatibility with older versions of Windows.
It's important to remember that shortcuts only reference programs so merely deleting a shortcut from the desktop or start menu doesn't uninstall the program. This has to be done explicitly. Program that has not been uninstalled still consumes computer resources such as disk space, memory, registry settings etc.