If you can clarify the following, I can give you a specific answer:
Is this for Windows, Mac, or a specific gaming console? Common ways I can help once I know the contents: ReThink-3.rar
Is this a specific program (like a productivity tool) or a game mod (like for Minecraft or The Sims )? Purpose: What does the content inside the .rar file do? If you can clarify the following, I can