If you're running XP Pro click Start, Run and enter GPEDIT.MSC Go to:
Computer Configuration, Administrative Templates, Windows Components, NetMeeting
and
User Configuration, Administrative Templates, Windows Components, NetMeeting
Altenatively, you can simply uninstall it. Click Start, Run and enter:
RunDll32 advpack.dll,LaunchINFSection C:\WINDOWS\inf\msnetmtg.inf,NetMtg.Remove
Copy and paste the line above. Watch for line wraps.