VB中 如何判断程序是否在运行？？

Private Declare Function OpenProcess Lib "kernel32.dll" (ByVal dwDesiredAccess As Long, ByVal bInheritHandle As Long, ByVal dwProcessId As Long) As Long
Private Declare Function GetExitCodeProcess Lib "kernel32.dll" (ByVal hProcess As Long, ByRef lpExitCode As Long) As Long
Private Declare Sub Sleep Lib "kernel32.dll" (ByVal dwMilliseconds As Long)
Private Const PROCESS_QUERY_INFORMATION As Long = (&H400)
Private Const STILL_ACTIVE As Long = &H103
Public hShell As Long, hProc As Long, lExit As Long
Private Sub Command1_Click()
hProc = OpenProcess(PROCESS_QUERY_INFORMATION, False, hShell)
GetExitCodeProcess hProc, lExit
If lExit = STILL_ACTIVE Then
MsgBox "程序正在运行"
Else
hShell = Shell("cmd.exe")
End If
End Sub