Right-click on Part 1 only . Select "Extract Here" or "Extract to Postal.4...". The software will automatically pull data from all other parts to recreate the full game folder. You do not need to extract the other parts individually.
To install and play from a multi-part RAR archive (specifically version 1.1.0), you need to extract the files into a single folder and run the game's executable. Postal.4.No.Regerts.v1.1.0.part1.rar
Once extraction is complete, open the newly created folder (usually named Postal 4 No Regerts ). Run the Game: Right-click on Part 1 only