No internet after uninstalling NIS 2009

Hi people, I have two computers. One with Vista SP 1 and the other one with XP SP3. In both I have NIS 2009 purchased and installed.

 

Some weeks ago I uninstalled it in Vista laptop. I did it in the Add/Remove programs and the uninstall went fine without any prob. At the end it asked me to restart my computer and I did it.

 

When I restarded my computer internet didn't work at all. I checked my other laptop with XP SP3 and internet didn't work either.

 

I tried to fix but nothing worked. Finally I reinstalled NIS 2009 and after restarting the computer internet worked again. So the problem was something related to NIS.

 

In some weeks/months I'm planning to unistall it again and I wouldn't like to have the same problem again. So I want to ask you for help on how to solve that problem.

 

Thanks in advance.