c# 'Invalid class' in a simple WMI query

I solve my problem. It seem that my WMI was corrupt. After testing WMI with this step:

1. Click Start, click Run, type wmimgmt.msc, and then click OK.
2. Right-click WMI Control (Local), and then click Properties.

I saw Win32_Process was a invalid class I follow this step for repair my WMI, and it work

1) In the start menu type "cmd"

2) Type "net stop winmgmt" and press Enter

3) Open a Windows Explorer and locate the path to C:\ windows\system32\WBEM\ folder and rename the Repository folder to something else like RepositoryOLD (right click and choose 'Rename Folder').

4) restart the computer

5) In the start menu type "cmd"

6) Type "net stop winmgmt" and press enter

7) Type "winmgmt /resetRepository" and restart the computer.

As dominus suggested, use the Process class:

...
Process[] processes = Process.GetProcesses();

foreach (Process process in processes)
    Console.WriteLine(process.ProcessName);
...