Many users know how to get videos and music off existing sources that were designed to be viewed live, eg youtube, whether it’s using a downloaded program or a 3rd party website that rips the content and allows you to download it.
Users wanting to download somebody else’s video of Facebook will realize this isn’t possible, and third party methods are most probably ruled out because of privacy settings.

There is a way though, using your browsers (Firefox in this case) cache. A cache is a copy of something that your computer stores enabling you to access it faster next time, without the need to re-download the content from the server.

1. Go to the video page using Firefox, don’t play it yet.
2. Click the Start button, click your user name that you’re logged into Windows with. eg mine is LEthaLity. You should see a folder called AppData, if you do skip to step 4, if not, read on.
3. You need to enable the viewing of hidden folders, click the organise button in the top left, ->Folder and Search Options, then click the View tab, under Files and Folders there’s a “Hidden files and folders” option. Click the radio button enabling “Show hidden files, folders, and drives”. Then click Apply, and ok, you should now see AppData.
4. Enter AppData, then click Local->Mozilla->Firefox->Profiles. You will then see a folder named in the following manner “imm40evz.default”, the bit before default will probably be different for you. Enter this folder, then go into Cache.
5. Click “Date modified” so it reorders everything, with the last altered files/folders at the top.
6. Keeping that folder open, now return to Firefox and play the video all the way through, making a note of the time on your pc when the video finished. Go straight back to that folder, something will have changed, a folder should now have a “date modified” time dating back to the last few seconds, there may be more then one but we’ll deal with this next.
7. Enter a recently modified folder and find the file that’s altered at the same time, for a video of 30+ seconds you can expect the file size to be a few Mb’s, larger then other things being cached. I recommend right clicking suspect files, selecting “copy”, then right clicking in a blank space on the Desktop, and “pasting” any files there.
8. Next we need to verify if/whether the files are videos, we can’t rely on a file extension because there is none, the filenames are quite random eg. 744C1d01. We will use VLC, a program that can play nearly all types of media. Go to http://www.videolan.org/ to download it if you don’t already have it. Once it’s downloaded and installed, double click one of the files, you should be asked which program you want to open it with. Select VLC media player, when it opens, if it’s a video you will see a video playing in VLC, if not then try another file.
9. Now you’ve hopefully found what you were after, you want to rename the file so you can open it in a “normal” media player eg WMP. Just right click the file, click rename, give it a file name of your choice, and add .mp4 to the end. Turning your useless file named  “744C1d01″ into something more appealing like “The wedding.mp4″. With the .mp4 extension (you can try other recognised video formats) you should find that double clicking the file will automatically open it in a media player without you needing to choose, for most people this will be Windows Media Player.

   That’s it for this “How-To”, I will try and make a video to accompany this. Hope you find it useful.