If this file was unexpected, downloaded from an untrusted source, or arrived via email, it is highly recommended to scan it with an antivirus program before opening it.
You will need archive software like WinRAR or 7-Zip to look at the contents of a .rar file. isus.rar
did you find "isus.rar" (e.g., inside a software folder, email attachment)? If this file was unexpected, downloaded from an
are you trying to do with it? (e.g., scan it for safety, extract its contents, know what it belongs to)? If this file was unexpected
"ISUS" sometimes refers to "InstallShield Update Service."