These errors do not always mean your system is broken. Often, the issue is a on a CD or a truncated download from an abandonware site.
Unlike generic system files (like dll files), data1.cab is not a universal Windows system file. It is specific to the software you are trying to install. data1.cab file download
Before you rush to download a replacement file, you must diagnose why the error is occurring. It is not always a case of a missing file; sometimes, the file is there, but the system cannot read it. These errors do not always mean your system is broken