Install an OS from a Trusted Source

This almost always means the OS install disc, preferably an official licensed copy with hologram intact.

An alternative would be to create a custom OS install disc or a private bootp/ftp server that already includes patches (and possibly some standard applications). Windows installers will want to start by researching slip streaming.

NOTE: while in the process of installing the system, do not use blank or default passwords. Always use good habits.