+1  A: 

The services are not returned in alphabetical order. You need to sort your results otherwise you will have to hunt through the list to find them. They are all there in my tests.

My sample code:

ManagementObjectSearcher mos = new ManagementObjectSearcher("select * from Win32_Service");
foreach (ManagementObject service in mos.Get())
{
    listBox1.Items.Add(service["DisplayName"]);
}
listBox1.Sorted = true;
Jack B Nimble
Thank you. I noticed it and fixed the problem but forgot to update the answer.
Sung Meister