How to check programmatically if WSS or MOSS are installed

I came into a situation when I needed to check if a SharePoint installation exists on a system, and specifically, WSS (Windows SherePoint Servises) or MOSS (Microsoft Office SharePoint Server).

The two properties can be useful in this case, the idea depends on checking the registry.
Note that I extracted this code from the open source project SharePoint Solution Installer and made minor modifications.

To check for WSS we check the key:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\12.0]
and the value "SharePoint" must be "Installed"

To check for MOSS we check the key:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office Server\12.0]
"BuildVersion"="12.0.4518.1016"
and check that the version is 12

Here is the code:

public static bool IsWSSInstalled
{
get
{
string name = @"SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\12.0";

try
{
RegistryKey key = Registry.LocalMachine.OpenSubKey(name);
if (key != null)
{
object val = key.GetValue("SharePoint");
if (val != null && val.Equals("Installed"))
{
return true;
}
}
return false;
}

catch (SecurityException ex)
{
throw new Exception("Access deined. Could not read the Windows Registry key '" + name + "'", ex);
}
}
}

public static bool IsMOSSInstalled
{
get
{
string name = @"SOFTWARE\Microsoft\Office Server\12.0";

try
{
RegistryKey key = Registry.LocalMachine.OpenSubKey(name);
if (key != null)
{
string versionStr = key.GetValue("BuildVersion") as string;
if (versionStr != null)
{
Version buildVersion = new Version(versionStr);
if (buildVersion.Major == 12)
{
return true;
}
}
}
return false;
}

catch (SecurityException ex)
{
throw new Exception("Access deined. Could not read the Windows Registry key '" + name + "'", ex);
}
}
}

and at the top of your class:
using Microsoft.Win32;
using System.Security;