You will need to use the System.DirectoryServices namespace and try the following:
DirectoryEntry root = new DirectoryEntry("WinNT:");
foreach (DirectoryEntry computers in root.Children)
{
foreach (DirectoryEntry computer in computers.Children)
{
if (computer.Name != "Schema")
{
textBox1.Text += computer.Name + "\r\n";
}
}
}
It worked for me.