How to recognize a path inside a string

bool isPath = System.IO.Path.GetDirectoryName(@"C:MyFolderSomeFile.exe -i -d") != String.Empty;
if (isPath)
{
    Console.WriteLine("The string contains a path");
}

C:My FolderSome File.exe -i -d
=>
C:My FolderSome File.exe -i -d (no, although it might exist!)
C:My FolderSome File.exe -i    (no)
C:My FolderSome File.exe       (yes => That's this one)