• Windows Media
• Real Player One
• Real Player and Firewalls
• Quicktime
• Macromedia Shockwave
• Macromedia Flashplayer
• DivX Codecs

This is the most common player used for video/audio, and it's always good to have the latest version installed on your computer.

Download Windows Media Player : Download
Windows Media Player Support Centre : Windows Media Support

The below link is direct to the free player, use caution if you go to real.com as the free player is hard to find.
Download the free RealOne Player from Real.com: Download Real One

Firewalls and the RealSystem

Support Link: RealSystem Firewall Support

Firewalls create barriers in order to prevent unauthorized access to a network. Think of the internet as a series of hallways. Firewalls are the security doors through which some people (i.e. data) may pass and others may not.
RealSystem content usually passes through these barriers without trouble, but sometimes it is necessary to change your configuration settings. With the proper configuration settings, you can enjoy RealAudio and RealVideo.

To Determine whether your computer is behind a network firewall :
If you received an error message about a firewall when you tried to play clips, or if you are not sure whether a firewall is preventing you from playing content, find out for sure by asking your Network Manager or Internet Service Provider.

AOL and other common ISPs :
If you are connecting to the Internet via AOL, MSN, Earthlink, Sympatico, Mindspring, Netcom, Sprynet, Compuserve, Prodigy Internet, or another common Internet Service Provider, you should not need to configure RealPlayer for use with a firewall. If you are having problems reaching most RealAudio or RealVideo content, contact RealNetworks technical support.

Playing content through a firewall :
If you have determined that your computer is connected to a network protected by a firewall, use the appropriate instructions below to enable RealAudio and RealVideo access:

Configure RealPlayer 8
Configure RealPlayer 7
Configure RealPlayer G2
Configure RealPlayer 4.0 & 5.0
Configure RealAudio Player 3.0

RealPlayers behind a firewall may experience difficulty playing content from sites on the Internet if the firewall is not configured to allow RealPlayer traffic. If you are behind a firewall, and are attempting to play content from the Internet, the firewall may be preventing you from playing content if you observe the following symptoms :

• You are accessing the Internet via an Internet Service Provider or a cable modem and have trouble connecting to RealAudio or RealVideo files on some or all Web sites.
  
• You are on a local area network which is attached to the Internet, and are unable to play RealAudio and RealVideo files from some or all remote Web sites.
  
• You receive one of the following errors:

  "Error 18: Invalid socket error"
  "Error 22: Requested server is not valid"
  "Error 108 : Invalid Auto Transport Configuration Setup"
  "Error 38 : File compression not supported. Cannot locate the requested RealAudio decoder" (on UNIX machines) when attemping to play content over the Internet

Quicktime is generally used for any file with the extension ".mov". It supports many other video/audio formats as well, but not all.

Download: Download Quicktime
Help Page: Help from Quicktime

Download the Shockwave plug-in : Download Shockwave
Shockwave F.A.Q. : F.A.Q.

Flash is becoming increasingly popular all over the web, and it's a good idea to keep your flash player up to date.

Download the Flash player : Download Flash
Flash F.A.Q. : F.A.Q.

This is the latest technology to hit the scene, and DivX codecs are required for some newer videos, their player is also included in the bundled download (although it's not required to play DivX encoded files).
For best results use the DivX player for DivX encoded files instead of Windows Media Player. Windows Media will automatically use the codecs you require from DivX, but you may experience some severe visual distortions.

Download: DivX Codecs