Global Assembly Cache (GAC)

The Global Assembly Cache (GAC) is a machine-wide .NET assemblies cache for Microsoft's CLR platform. The approach of having a specially controlled central repository addresses the shared library concept and helps to avoid pitfalls of other solutions that led to drawbacks like DLL hell. - wikipedia

Note: 'c:\windows\assembly' consists of subfolders like 'GAC, GAC_32, GAC_MSIL, GAC_64...' that contain the dll's but win shell stops you from browsing to it.

So you don't have Gacutil.exe or afraid to use it here is some alternative to get dll's in and out of the GAC.

1. Map the assembly as a drive in windows explorer.

'\\[machine name]\c$\windows\assembly'

2. Run cmd as admin and type start full gac path you want

'start %windir%\assembly\GAC_MSIL\'