Ten ways to protect yourself online:

Make sure your operating system’s automatic updates and firewall are turned on.
Use security programs, including anti-virus and anti-spyware software, and subscribe to security updates.
Run a full system scan at least once a month.
Don’t open attachments or click on links in e-mails from people you don’t know.
Use passwords with at least [...]

A bot is a computer whose operation has been secretly hijacked by malware. The infected computer, which is often referred to as a “zombie,” has a Trojan program which directs the computer to connect to a remote location to download additional instructions. A group of hijacked zombie computers forms a botnet.
In the second half of [...]