Try this. Open the Project menu, select Add Existing Item, and add the PDF file to the project. In the Properties window, click on the file and then set its "Copy to Output Directory" property to "Copy if newer." It should copy the PDF file into the executable directory when necessary.
That should make it work when you're running in the IDE or in the output directory, which is something like bin/Debug.
In the installation project, make sure to copy the file to where ever you put the executable.
Take a look at the installation directory and see of the file is present.
If it's there but the program can't open it, try putting a statement like the following in the program just before it tries to open the file.
MessageBox.Show("Operations Guide.pdf exists: " & _
System.IO .File.Exists("Operations Guide.pdf"))
That should tell you whether the program can find the file at all.
If that doesn't work, you could try changing the name of the file to something simple without the space like "OperationsGuide.pdf." I don't think it should be confused by the space but ...
If the file's path is too long, you may also have trouble. I doubt it would be too long (the limit is pretty big) but you could try a shorter name like "Guide.pdf."
Be sure to put a Try Catch block around the call to Process.Start and make the Catch block display the exception's message so you can see what it thinks is going wrong. Note that the system where you install the program won't be able to open the file if it doesn't have Acrobat Reader installed.
I hope that helps. Keep me posted.