Flv Recorder have a build-in flv player, so you just double-clicked the recorded files(.flv) in the recording list, you can watch the recorded videos.

If the recorded files are MP3, MP4, or other media format, then you need other player(WMP, RealPlayer, Winamp, Quicktime) to play them.

You can also click the "Open File" menu(below pic), then select the .flv file to play.