How to copy DLL or take backup of GAC

1. Go to Start >> Run
2. enter command C:\WINDOWS\ASSEMBLY\gac_msil
3. this will give you the explorer windows with all the folder containing each available .dll in GAC
4. If you like to take backup of all dll then copy all of them or find folder name as per the dll name to copy just specific dll

To Install the dll in GAC without utility

1.  Open the folder C:\WINDOWS\ASSEMBLY
2.  Drag and drop the dll in to this folder.It will get installed.

Hope this will be useful.