VB Forum / General / July 2008

Here is the code I use for that situation

Const SE_ERR_NOASSOC = 31

ShellRet = ShellExecute(Me.hwnd, "Open", MyFile, 0&, 0&,SW_SHOWNORMAL)
   If ShellRet = SE_ERR_NOASSOC Then
       Shell "rundll32.exe shell32.dll,OpenAs_RunDLL " &
MyFile,vbNormalFocus
   End If

Basically, the same thing you get in Explorer when you double click a file
with no association.

HTH

Matt