If part04 is the only file you have, you cannot access the data. You must download the remaining parts from the original source.
if your security software flags them as "Trojans" or "Malware." To help you further, could you tell me: Do you have all the other parts (01, 02, 03, etc.)?
The software will automatically "stitch" part04 and all other parts together. Grand.Theft.Auto.part04.rar
Right-click ( Grand.Theft.Auto.part01.rar ). Select "Extract Here" or "Extract to [Folder Name]" .
Which is this (GTA V, San Andreas, etc.)? If part04 is the only file you have,
Are you getting a when you try to open it?
Ensure you have all numbered files (e.g., part01.rar through partXX.rar ). Grand.Theft.Auto.part04.rar
with updated antivirus software (like Windows Defender or Malwarebytes).