authentication window does not prompt me to register

See more: (untagged)

I have a business application installed on my desktop with XP Pro (sp3). This is a client side application. When I open the application, it will first authenticate my system by extracting my system id in the authentication window. In the same window, I am supposed to enter the serial key provided by the owner. Only then, my system will become an authorized system for running the business application. The problem here is, when I run the application, it directly opens up without prompting me with the authentication window. The problem started recently when I had to re-install XP pro (sp3) due to system crash. I found a ray of hope in this forum where I realized to install IIS, and unchecked "enable anonymous access" and checked "integrated windows authentication". But still, the problem persists.Is it required at the client side?
Kindly help.

PN: 1) It required .net framework 3.5 (SP1) which I have installed already.
2) I installed XP on D: and not on C: (application was working when os was on c:)
3) Application is installed on my desktop, so i feel it should be offline/intranet app.