Goto Registry[Run --> regedit], Add below binary key in this path: HKEY_LOCAL_MACHINE --> SOFTWARE --> Microsoft --> Fusion --> New Binary Value :

Name as DisableCacheViewer and Value as any non-zero value. Now, open the GAC present in C:\Windows\assembly. Its view will be changed to a normal windows explorer view. If the view not changed, either restart the m/c or kill and start the explorer.exe process from Task Manager.