When you reply, please include enough context so that someone can read
the post from top to bottom and follow the conversation.

Since this is a Java news group, I can't really help with the actual
code here unless you want to try solving the problem in Java.  If you
really want to stick with VB, try posting your code in a VB-related news
group.

It sounds like your program is getting invoked whenever the user opens a
relevant file (PDF), so your program can do whatever it likes when that
happens.  In order to keep a count of the number of times the program
has been invoked, your program might include the following steps:

    - try to open a config file for read/write, e.g.
     %HomeDrive%%HomePath%\_yourProgramRC
    - read the count from the file if it is present, else initialize
     the count to zero
    - overwrite the file contents with the new count, i.e. the old
     count plus one
    - run adobe, passing it the relevant command-line arguments and
     process environment

The current count will always be stored in the config file.