i cant view none of my programs recongize the file.
Your problem is that you're trying to view it through a third-party program such as Windows Media Player. You don't use those to view demos, you do it right in your game.
You need to put the .dem file you downloaded from RapidShare into your
"C:\Program Files\Steam\steamapps\(username here)\insurgency\insurgency" folder, assuming you're on Windows. When you're done with that, go into Insurgency, open up the console, and type
"PlayDemo rpg_contest", without the quotes of course. It should then start playing the demo right in your Insurgency game.
You can use this method to watch any Insurgency demo you download off the internet. Just move the .dem file to the folder listed above, then use the
"PlayDemo filename" command, where 'filename' is replaced with the name of your demo file. Any demos you record yourself using the
"Record filename" command will automatically be placed in the right folder, so all you'll have to do to play those is just type
"PlayDemo filename" without having to move anything.
I know it sounds a bit confusing at first, but once you get the hang of it, it becomes second nature.