Your file is not damaged. You were probably shooting MP4 that was then wrapped in a MOV container. MOV was developed over at Apple with Quicktime, so it is native to Mac computers. You might want to download Quicktime for Windows from Apple’s website and you should be able to view it with Quicktime. Another option is downloading a free MOV to MP4 converter that just changes the container from an MOV to MP4 container, or even get a converter that can convert the MP4 to another codec, such as AVI.