What is it?
Microsoft Shell Library - shell32.dll

What does it do?
The Microsoft Windows user interface (UI) provides users with access to a wide variety of objects necessary for running applications and managing the operating system. The most numerous and familiar of these objects are the folders and files that reside on computer disk drives. There are also a number of virtual objects that allow the user to do tasks such as sending files to remote printers or accessing the Recycle Bin. The Shell organizes these objects into a hierarchical namespace, and provides users and applications with a consistent and efficient way to access and manage objects.

Microsoft's information page.

Virus Precautions:
You'll want to keep an eye on this google search for any known viruses. The normal location of this file is C:\windows\system32\shell32.dll


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