submit issues

OK, this must be a very very simple question for ASP programmers to answer.
After I have gathered all the information I want from the user and after
the user has clicked on a submit button, how do I make an operating system
style call on the server.
Now, I have already figured out how to create a function call in the ASP
development environment that is called when the user clicks on the submit
button.
So my qesttion is to how to create a system level command through ASP.
Specifically, I am using ASP.NET.* Let me explain further.* I have just completed
a program that is very simular to the #3 AJAX demo that Joe Strgner has made on
where he gets users to select from a group
of "CascadingDropDown" control extender classes.* When the user has selected
from the third drop down control, a label is custom formatted and displays the
group of selected options.
What I want to do is this.* After this is done, I want to have a "submit" button
on this page which, when the user presses it, a call is made on the server side
that will include the users selections as parameters.
Something like this, for example:
"CALL SOMEPROGRAM.EXE " selection_1, selection_2
I need to have some information specific to the user included in the submit.
We are on an intranet and each user has an alias.* How do I snag this information?