I having problem how we open a pdf file in vb.
If you want to open it use this:
System.IO.File.Open("C:\HI.pdf", System.IO.FileMode.Open)
If you want to open pdf on your windows form page, in Visual, in toolbox menu choose WebBrowser by double clicking on it, you see a new webbrowser shown on your form page, click on the webbrowser, and go to the proporities panel, in the panel you see the URL Text, then write the pdf path to the URL TextBox.
bye.