Avast Anti virus - Protects your PC from security attacks.
Believe it or not, for MOST users, this is sufficient protection, and the price is right!
Download it here: https://www.avast.com/
SyncBack- Use this program to keep your data synchronized and backed up.
Download it here: https://www.2brightsparks.com/download-syncback.html
HiJack This! - Use this program to analyze system files for tampering. BE CAREFUL!
This tool is NOT for the timid!
Download it here: https://sourceforge.net/projects/hjt/
Handbrake - The Open Source Video Transcoder.
Download it here: https://handbrake.fr/downloads.php