I have a laptop computer and i don't know how to activate the cam for my messenger?

There are many messengers one can use on mac,and I am not clear which one you are referring to. I am therefore providing many answers about many ways you can message and videoconference on mac. msn messenger does not have video conferencing for macs.( I also searched for some time to discover this!) You can get msn messenger for mac (the download) but it does not include video chatting!! I am sure of this. There is also a download for Yahoo messenger for mac which includes videoconferencing http://messenger.yahoo.com/mac/, However, Skype is great for mac videoconferencing. (My favorite). Gmail also has something to download for videoconferencing also. http://www.google.com/chat/video. There is also Ichat for macs http://docs.info.apple.com/article.html?path=iChat/4.0/en/15610.html and this is the page with info about setting it up, and AIM. And here is a tutorial for ichat and AIM video conferencing: http://www.mvldesign.com/video_conference_tutorial.html. ...... However.... I personally love Skype. Download it at Skype.com, create user name and password and then invite contacts. To activate the cam go to Skype preferences on the top of the screen, choose video and check off Enable Skype video to see your friends and also check off Start Automatically if you want them to to see you (or you can click the icon for the video after you are on a call with them for them to see you only if you want to be seen on that one call!). If you find this answers your question I would so much appreciate a positive vote!