Hi. Belarc Advisor says I need the above security fix installed on my XP Home system. I've downloaded and tried to install from my desktop, KB954156-32bit-x64-ENU.exe and get the error message: "Update\update.exe is not a valid Win32 application." I also downloaded and tried to install KB954156-32bit-x84-ENU.exe from my desktop and received the following error: "Windows Media Encoder must be on your machine before this software can be installed. Please install Windows encoder and launch this software update again." I am not a professional. I have Windows Media Player 11 on my computer. It's used solely for viewing video files. I don't know if KB954156, a security fix for Windows Media Encoder 9 is part of Media Player 11, or if it's a separate application. Windows Media Encoder 9 does not show up under Add/Remove Programs so I have no idea if it's installed. I assume it is or Belarc Advisor would not tell me I need this Critical Update. Although I'm a novice, my research before finding this site leads me to believe Encoder 9 is necessary if I want to convert files and use my video cam for making streaming video. I do not. I use my webcam only through Yahoo Messenger as part of chat. However, if Media Encoder 9 IS on my computer, I certainly want this Security Update. I'm very concerned my computer has a security deficiency but am at a loss as to how to fix it. I attempted to contact Microsoft Support through their website but the process hung up on "Loading........." my computer information after I outlined this problem. I assume my request for help was not sent or received. I'd really appreciate your help in easy to understand layman's terms. Thank you very much.