Welcome to Discussions, abicsangree
why does my iSight quit wheniever i vid chat/screen share?
This is how iChat Screen Sharing works. iSight is not actually quitting.
"Screen sharing" lets you SEE the other person's screen, so your monitor stops showing your iSight and uses the video bandwidth to show you what the other person sees on his display.
what can i do to help it?
Nothing. This is how Screen Sharing is designed to work. Audio chat, but not video, continues as explained in
http://docs.info.apple.com/article.html?path=iChat/4.0/en/11883.html
After you have stopped screen sharing, you should be able to quit the audio call that is in progress and call back on video to restore your video chat connection.
EZ Jim
G5 DP 1.8GHz w/Mac OS X (10.5.6) PowerBook 1.67GHz (10.4.11) iBookSE 366MHz (10.3.9) External iSight