Rendering an Animation or an Image Renders an Older Version of the File?

I have been working on a YouTube intro. I stopped half way but now I have been asked to finish it. I changed some things to the blender file (colour, redid the physics simulation and improved the texturing/materials). However, when I went to render the final product I found that it was rendering the file that I had prior to the new work. I have not installed an updated version of blender (I’m on version 2.69). Can someone please help? Thanks in advance…

Check the video sequence editor and compositing node editor to see if they have anythng loaded. These will override the 3d view render unless you disable them in the Render / Post processing panel.