Go To WinRAR download trial version from here: 32Bit, 64Bit OR If You Already Have It Installed Follow The Steps Below.
Install Like Any Normal Program
Now Go into Your Program Files & Drag This Key Into The WinRAR Directory (C:\Program Files\WinRAR)
***Please note if you cant find the WinRAR Folder In The Program Files Directory You Probably Installed 32 Bit Version On A 64 Bit Machine If You Do i Recommend You Uninstall The 32 Bit And Install The 64 Bit***