The problem with some capture software, especially the free kind is that the codec used for compression, etc. is often outdated or just plain corrupted. Or it can only be viewed with one player or editor, but not another.
If you plan on using screen-capture on a regular basis or just want something reliable and affordable, I would suggest you get the the one that gamers use. I've used it to take high res captures of NASA WorldWind (kind of like Google Earth freeware just for satellite images) where I could simulate fly-overs.
Its captures have never failed to work or show up in my video players or video editing software.
It's solid, it's got great support, and it's only USD $37. You can see/download some of the examples on the homepage. And you can try it out before you buy (you'll just get a watermark on the video until you buy it).