Why doesn't the picture show up when i convert video files?

Me and My friend recorded us doing the cotton eye joe dance for youtube. When I put the videos from my phone onto the computer the appeard as 3gp for the first time ever. They will not work on windows movie maker so i downloaded 3 different types of converters, each one coverts the audio but the screen is blank. Why wont it convert the video to? HELP!!!!

Free Download, Flv to 3gp Software Collection Download.

This article shows you how to Extract audio from Flash video, FLV to MP3(MPEG Layer-3).

Software for 3gp 3g2 video converting, convert any video to 3gp 3g2.

I recommend you xlink 3gp to video converter with relatively good quality and editor function,it is really good.
I have been using it 3 weeks. I found I can edit my videos any way.it seems that I have 2 different softwares,but I only need pay for one. You can share videos with friends on the go.
Hope can help you.
To perfect your life!
you can download it here:http://www.xlinksoft.com/3GP-to-video-co...
Maybe it is your best choose,have a try

It can convert almost any the video format to another with high output quality.
This full-featured video converter software also can help you:
1.convert between all mainstream video and audio formats,such as(mp4, 3gp,mov, m4v, vob, XviD, avi, flv, 3g2, mpg,wmv,etc;m4v, mp3, wav, ac3,etc)
2.extract audio tracks from video files to other audio formats
3.support all popular portable multimedia players
4.edit video-Merge, Trim, Crop and Snapshot
Just try now.Hope this can help you