Antivirus software - used to protect a computer from viruses, computer worms, and Trojan horses. It also removes or prevents spyware and adware.
Spyware Protection - Protects against programs that secretly record what you do on your computer. They are mostly used to capture passwords, banking credentials and credit card details.
De-fragmentation - the process of consolidating fragmented data on a volume (such as a hard disk or a storage device) so it will work more efficiently.