From C# code:

I have com add-in to outlook 2003, code in c#.
I want to check if this add-in already installed in this computer.

private void isOutlook()
{
Microsoft.Win32.RegistryKey key =
Microsoft.Win32.Registry.LocalMachine.OpenSubKey(" Software\\microsoft\\windows\\currentversion\\app paths\\OUTLOOK.EXE");
string path = (string)key.GetValue("Path"); if( path != null)// if have
outlook do the installing com add-in
//if this com add-in not yet installed

System.Diagnostics.Process.Start("C:\\MatarotToolb ar\\MatarotToolbarSetup\\Debug\\Setup.Exe");
}