The Recycle bin is a Desktop Icon which contains files which have been deleted recently.
Uses of recycle bin:
• Restore files and folders from the recycle bin.
• Empty recycle bin to delete data (You will be lost all data forever).

The majority of new antivirus programs enable users to update their antivirus program through the software. 
Open the Virus program and look for “Update”, “Check for updates”, “Live Update”, or something similar. It means the antivirus will detect new viruses if it is updated.

Web sites: A web site is a simply a group of file and folders which are stored on a WWW server and which can be freely accessed by people(s) “surfing the Web”. For instance Microsoft has Web site is www. Microsoft.com etc.
URLs: The address of a Web site is given but something called its URL (Uniform resource locator)

A firewall is a system that secures our network from access by unauthorized users and a firewall is consists of software & hardware protection against invasion via the Internet.

Spam is one kind of unwanted E-mail(s). We should be very careful about entering our E-mail address forms on web sites which is not familiar with us. We may later get unsolicited E-mail (called spam) from the web site.