Determine OS using Environment.OSVersion [duplicate]

The following should work. But why do you care? Is just for informational purposes in logging or are you looking for actual capabilities being present on the target platform?

if (Environment.OSVersion.Version.Major == 5)
{
    if (Environment.OSVersion.Version.Minor == 1)
    {
             // XP
    }
    else if (Environment.OSVersion.Version.Minor == 2)
    {
             // Server 2003.  XP 64-bit will also fall in here.
    }
}
else if (Environment.OSVersion.Version.Major >= 6)
{
        // Vista on up
}

Not a complete list, but got this from http://support.microsoft.com/kb/304283:

+--------------------------------------------------------------+
|           |Windows|Windows|Windows|Windows NT|Windows|Windows|
|           |  95   |  98   |  Me   |    4.0   | 2000  |  XP   |
+--------------------------------------------------------------+
|PlatformID | 1     | 1     | 1     | 2        | 2     | 2     |
+--------------------------------------------------------------+
|Major      |       |       |       |          |       |       |
| version   | 4     | 4     | 4     | 4        | 5     | 5     |
+--------------------------------------------------------------+
|Minor      |       |       |       |          |       |       |
| version   | 0     | 10    | 90    | 0        | 0     | 1     |
+--------------------------------------------------------------+

Edit: Note, the information returned by System.Environment.OSVersion may be unreliable if the application is running in compatibility mode.

Edit2: I would recommend you just make it a configurable value in your application - that way your code does not need recompilation when a new OS comes out, e.g., Windows 7.

If you dont have to be specific about R2 of server editions, a simpler alternative is:

enum OS { _2000, XP, Server2003, Vista, Server2008, _7, Server2012, _8 }

const int OS_ANYSERVER = 29;

[DllImport("shlwapi.dll", SetLastError = true, EntryPoint = "#437")]
static extern bool IsOS(int os);

static bool isWindowsServer = IsOS(OS_ANYSERVER);

public static OS GetOS()
{
    var version = Environment.OSVersion.Version;
    switch (version.Major)
    {
        case 5:
            switch (version.Minor)
            {
                case 0:
                    return OS._2000;
                case 1:
                    return OS.XP;
                case 2:
                    return isWindowsServer ? OS.Server2003 : OS.XP;
            }
            break;
        case 6:
            switch (version.Minor)
            {
                case 0:
                    return isWindowsServer ? OS.Server2008 : OS.Vista;
                case 1:
                    return isWindowsServer ? OS.Server2008 : OS._7;
                case 2:
                    return isWindowsServer ? OS.Server2012 : OS._8;
            }
            break;
    }

    throw new Exception("Strange OS");
}

Copied from here.

To be more specific your options are,

1. WMI, you will have to some manual parsing. Not sure if user privilege is going to hurt non admin users.

2. GetVersionEx as described in this answer.

3. Checking for ProductName at

   HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\
   

if(Environment.OSVersion.Version.Major > 5) { /* vista and above */ }