VB won't show PDF Reader - vb.net

Question

I use the following Code to Open a PDF File:
Public Sub Execute_Doc(afilename As String, Optional style As ProcessWindowStyle = ProcessWindowStyle.Minimized)
Dim myProcess As New Process
Const ERROR_FILE_NOT_FOUND As Integer = 2
Const ERROR_ACCESS_DENIED As Integer = 5
Try
myProcess.StartInfo.FileName = afilename
myProcess.StartInfo.WindowStyle = style
myProcess.Start()
Catch e As System.ComponentModel.Win32Exception
If e.NativeErrorCode = ERROR_FILE_NOT_FOUND Then
Console.WriteLine(e.Message + ". Check the path.")
MsgBox("File<" + afilename + "> not found!")
Else
If e.NativeErrorCode = ERROR_ACCESS_DENIED Then
Console.WriteLine(e.Message + ". You do not have permission to print this file.")
MsgBox("File <" + afilename + "> couldn't be opened!")
End If
End If
MsgBox(e.ToString())
Catch ex As Exception
MsgBox(e.ToString())
Finally
myProcess.Kill()
myProcess.Dispose()
End Try
End Sub
I call Execute_Doc("C:\ProgrammName\Test.pdf", ProcessWindowStyle.Normal) but the Adobe Reader won't show up. I can see it in the Task Manager.
Well it works if I start Adobe Reader first without any files by clicking the default Icon on my Desktop. It also works with the integrated PDF Reader from Windows 8.1. I can't debug this isse on my Windows 7 / VS 2013 Computer. The problem only exists on ONE! client computer.
Any tipps how to solve this?

Answer 1

Public Sub Execute_Doc(afilename As String, Optional style As ProcessWindowStyle = ProcessWindowStyle.Minimized)
Dim myProcess As New Process
Const ERROR_FILE_NOT_FOUND As Integer = 2
Const ERROR_ACCESS_DENIED As Integer = 5
Try
myProcess.StartInfo.FileName = "AcroRd32.exe " & afilename
myProcess.StartInfo.WindowStyle = style
myProcess.Start()
Catch e As System.ComponentModel.Win32Exception
If e.NativeErrorCode = ERROR_FILE_NOT_FOUND Then
Console.WriteLine(e.Message + ". Check the path.")
MsgBox("File<" + afilename + "> not found!")
Else
If e.NativeErrorCode = ERROR_ACCESS_DENIED Then
Console.WriteLine(e.Message + ". You do not have permission to print this file.")
MsgBox("File <" + afilename + "> couldn't be opened!")
End If
End If
MsgBox(e.ToString())
Catch ex As Exception
MsgBox(e.ToString())
Finally
myProcess.Kill()
myProcess.Dispose()
End Try
End Sub

Answer 2

Just use Shell Execute it is provided by the Win API so you do not have to worry about what program is installed to handle the extension. Windows does the work for you.
Private Function ShellExecute(ByVal File As String) As Boolean
Dim myProcess As New Process
myProcess.StartInfo.FileName = File
myProcess.StartInfo.UseShellExecute = True
myProcess.StartInfo.RedirectStandardOutput = False
myProcess.Start()
myProcess.Dispose()
End Function