This works with spaces in the folder name and
with spaces in the file name.
Code:
'put this in a bas module
'
 Public Declare Function ShellEx Lib "shell32.dll" Alias _
 "ShellExecuteA" (ByVal hwnd As Long, ByVal lpOperation As String, _
 ByVal lpFile As String, ByVal lpParameters As Any, _
 ByVal lpDirectory As Any, ByVal nShowCmd As Long) As Long
 '
 

'Form events
'open a file with it's associated application

Private Sub Command1_Click()
'
 Dim sFileName As String, x As Long
  sFileName = "c:\my documents\my special file.txt"
  x = ShellEx(Me.hwnd, "open", sFileName, "", "", 1)
'=====================================
End Sub