Your audio and Video in Windows live messenger is unable to run as you try to communicate with them. You troubleshoot them as possible with information available at you disposal but with no result. If you are using Mcafee the SiteAdvisor is the culprit. There is a quick solution to that.
First thing to do is to update your SiteAdvisor : Click on dropdown menu close to the Mcafee SiteAdvisor and click on download update. After downling the update run to install it and follow the instruction below.
Step 1: Go to you program folder. Click My computer --> drive C -->Programs -->Mcafee -->SiteAdvisor --> Sasets.ini (rightclick on it).Please, don't click on the ones with extention .dll.
Step 2: It will open up on the Notepad with several information about the messengers and other softawares the Mcafee SiteAdvisor is monitoring.
Step 3: Scroll down on the Notepad to look for msnmsgr.exe -->Enabled=1 -->change 1 to 0 ,like this Enabled=0
Step 4: Click File -->Save and Restart your system.
Step 5: Open your Windows live messenger and run your audio and video or simply open your webcam.