Unregister library DLL 

When you uninstall a program from your operating system, the uninstall process usually takes care of all the application files deletion, removal, unregistration, and other handling. However, in many cases, the uninstall process uninstalls the application files but does not do anything for the libraries.

Malware, spyware, spamware, and other insidious trash is a category on its own. These programs like to install libraries and leave them in your system. If you want to get rid of these programs, you have to unregister their libraries manually in many cases.

Unregistering a library can also be utilized when troubleshooting problems.

How do I unregister a DLL library?

Go to your Start menu, click the Run button and then execute the following command

regsvr32 /u <path & filename of dll or ocx>

An example of this would be

regsvr32 /u C:\WinNT\system32\ljjjki.dll

This example unregisters a library associated with a malware.

Why does a library DLL file need to be registered on a computer?

A Dynamic Linked Library (DLL) is a compiled collection of small programs, routines, etc. that are not immediately tied to an executable. A library sits still in the system and is used only when a program that calls it executes. Before the "calling" program starts, the library does not do anything.

Because libraries can be shared among programs, the Windows operating system manages libraries.

What does a Dynamic Link Library (DLL) do and why do we need it?

You can find more details about a Dynamic Link Library (DLL) at the following link: What is Dynamic Link Library (DLL)?

Regsvr32 syntax

Regsvr32 is used to register or unregister a Dynamic Link Library (DLL) and the following is its syntax.

REGSVR32 [/U] [/S] [/C] [/I:[Command_Line]] DLL_Name

/U          Unregister Server