Hello  every one I have serious problem when trying to install the program , after selecting which programs to be installed , after that I face now tap of system changes to accept with

this entry "The following firewall settings will be modified

Hello,

which system do you use (OS)?
Have you administrator privilegies?

Check the Following:
show if any error is reported in Windows Event Log
show if any error is in the install log Files, this files can be faound if you open Windows explorer and type
%AUTINSTLOG% in the adress tab, check the newewst LogFiles

Regards
Christoph

hi Mohammad,

If you want to REinstall, the "old" Step7-SW should be deinstalled fully and correctly, within all registry-entries etc. 

Therefore a FAQ will help you to deinstall everything on your PC: