cricketm- It may depend on the version you have installed, but it will be something like this: For Quicktime: Start Quicktime; click on Edit / Preferences / QT Preferences / Advanced. There should be a checkbox relating to Show Tray Icon. I believe that, if it's checked, the program begins at Startup; if it's not checked, it doesn't. For RealPlayer: Follow the directions in the link below...which are generally good for stopping other things too. Don't uncheck things if you don't know what they are, but obvious things like iTunes, or Adobe Acrobat can be unchecked. This is also another way of stopping QuickTime from running at start up if my directions above don't work for you. When you prevent things like RealPlayer from starting up, you do no harm. If you need them, you can always start them like any program, or sometimes clicking on a video will cause the program to start up. All you are sacrificing is having to wait a couple of seconds longer for something to start playing. But by not letting it run every time you boot up, you are freeing precious resources. Sometimes I don't use any video player for days, so I don't want it sitting there occupying my RAM on the off-chance that I'll be using it. Here is a link that might be useful: Prevent RealPlayer Running at Startup

Well now, ain't that just a kick in the ribs. You are correct. So I removed my Quicktime and re-installed the latest version hoping to have a tiny morsel of control during the install. How foolish of me! No chance that I had any options so I tried removing the associations again only to find as you did that they simply return. Oh how I hate these overbearing programs where programmers feel they are the only ones competent enough to know what we mere mortals need. I then removed Quicktime again and went looking for alternatives. At this point I only see sites I am not comfortable with to download from so I need to go searching around. Never liked any program that takes over and only had Quicktime because a web site I maintain has a QT file. However they have now created a Youtube presence so I can remove the QT junk and simply link to the Youtube site. Oh happy day. Later I'll search a bit more, in the meantime someone else may jump in with either a solution or a good QT replacement.

you can try www.zamzar.com it does a lot of various file formats for conversions. this is an open source free converter Any Video Converter Free Version Quick Media Converter is a free converter, you would want the English version.

Here's an explanation lifted from a webpage: A codec is software that is used to compress or decompress a digital media file, such as a song or video. Content creators use codecs because a compressed file takes up less storage space on your computer and can be transferred across the Internet more quickly and smoothly. When you play a digital media file, Windows Media Player uses a codec to decompress the file. Codecs are used to create and play nearly all music or video files on your computer or on Web sites. Q.Why do I get a message that says my computer is missing a codec? A.You are probably trying to play a file that uses a codec that is not on your computer. When you try to play a file that uses a codec that is not on your computer, the Player tries to download the codec from a Microsoft server. If the codec is available, the Player installs it on your computer and then plays the file. If the codec is not available on the server (for example, because the codec wasn't created by Microsoft), the Player displays a message that your computer is missing a codec. If you are connected to the Internet, the message usually has a Web Help button that you can click for more information. If the Player can determine which codec you are missing, when you click that button, a Help topic is displayed that contains a link to WMPlugins.com, a Web site that lists a number of codecs that are available to download. The MPEG-2 and DivX video codecs and the ACELP.net and Ogg Vorbis audio codecs are examples of codecs that are not included in the operating system or the Player by default. Q.How do I find a codec? A.When trying to find the right codec for a particular file, you can use WMPlugins.com or other Web sites. Typically, you should start with WMPlugins.com first. Recommend that you use caution when installing codecs that aren't listed on WMPlugins.com or Microsoft.com. If your computer is running Microsoft Windows Millennium Edition or Windows XP, we recommend that you set a system restore point before installing any digital media components. This enables you to return to your original system configuration, if necessary. If you get a message that you're missing a codec when you try to play a file, click the Web Help button on the message. In the Help topic that is displayed, click the link to WMPlugins.com. If you know the name of the codec you want to find, you can go directly to WMPlugins.com Codec. If the codec is listed on WMPlugins.com, follow the instructions on the page to download and install the codec. Q.Does the Player always try to download codecs automatically? A.It depends on several factors. To ensure the Player can try to download codecs automatically, you must have Internet Explorer 3.02 or later installed on your computer, maintain Internet access while playing the file, and your Internet security should be set to Medium. In addition, if your computer is running Microsoft Windows NT, Windows 2000, Windows XP Professional, or Windows Server 2003, you must be logged on as an administrator or as a member of the Administrators group. Finally, do the following: On the Tools menu, click Options. On the Player tab, select the Download codecs automatically check box. If you use the Player in a work environment that is managed by a network administrator, you might be restricted from downloading and installing software from the Web.