Dirt4.part7.rar -

This usually means DiRT4.part7.rar (or another part) didn't download correctly. You will likely need to redownload this specific part.

Check your download folder for DiRT4.part1.rar through DiRT4.partX.rar . You must have every single numbered part in the set. If Part 7 is missing its siblings, the extraction will fail. DiRT4.part7.rar

Once the process reaches 100%, you will see a new folder or an .iso file. This contains the actual game data. You can then run the setup.exe found inside that new folder to install the game. Common Troubleshooting This usually means DiRT4