For a Windows 98 Machine, you will need to have Windows Management Instrumentation installed. It is not installed on 98, 98SE, or ME by default. This link should give you what you will need to get that information.

http://support.microsoft.com/default.aspx?scid=kb;EN-US;322363

Larry

>Thanks, what I need is to get the manufacture s/n of Hard disk .. FYI I will run this on Win98 or later .. please advise.. I have below codes .. but it only work on XP and Win 2003:
>
>Dim mgmclass As New System.Management.ManagementClass("Win32_PhysicalMedia")
>Dim mgmcoll As Management.ManagementObjectCollection = mgmclass.GetInstances()
>Dim mgmenum As Management.ManagementObjectCollection.ManagementObjectEnumerator = mgmcoll.GetEnumerator
>mgmenum.MoveNext()
>MessageBox.Show(mgmenum.Current.Properties("SerialNumber").Value.ToString)
>
>the above codes will return the one that I can see on the sticker on the hard disk. but it works only XP and 2003