Where can i buy ImageMixer ver 1 for my sony dcr trv140 digital camera i lost mine and i never install

You can try eBay. But you really don't need ImageMixer (unless you really want to), since there are many video editing programs that are comparable to or better than ImageMixer. Video editing programs such as Ulead Videostudio, Pinnacle Studio, Adobe Premiere Elements, are all relatively low cost alternatives.)