Need To Make Simple Changes to Already Complete advertisement... how?

I had a video made almost a year ago that was an effective advertisement for my site. Once at the beginning, once in the middle, and once at the end, the domain name comes up on the screen for a few seconds each time. Since then, I changed domain names, and want the video on my new site, but with the updated domain name of course. Which program should I use and how can I edit out those few frames and replace them with the updated domain name?

I am looking for a free program since it should be a quick change.

Thanks for your help!

Its better if you find the original file. Like if it was made in after effects, look for the AE file.
Something like that. Other than that, i would rather recommend creating another video similar to that because its very hard to edit something frame by frame (assuming its 24 frame per second)
Good luck!

If you put some black bars (top/bottom to cover the URL) on the video...then add the new url over the black bars at the bottom. Editing indervidual frames will be very time consuming.

Free Software: hxxp://www.digitaltrends(.)com/computing/best-free-video-editing-software/ (replace xx with tt's and...you know the rest)