You cannot open this file individually to watch the movie. You must have all other parts (e.g., part1.rar , part2.rar , etc.) in the same folder.
Use a program like WinRAR , 7-Zip , or The Unarchiver . troyavext2004m1080g36.part3.rar
If Part 3 specifically shows a "checksum error," the file may have been corrupted during download and needs to be re-downloaded. You cannot open this file individually to watch the movie