A .part7.rar extension means this is just the seventh chunk of a larger, multi-part compressed archive. You cannot extract or use it without downloading all other parts (e.g., part1, part2, etc.).
Go back to the forum, thread, or index page where you found the download link to see if the author posted a description or a password. 5GBACVFF.part7.rar
If you are trying to figure out what this file is, consider these steps: etc.). Go back to the forum