Applications are not installing !!!

HEY,
I need help. I am using windows 7. In the start every application that i downloaded installed correctly. But now it started showing problem. No application is installing and shows dialogue box saying check your internet connection and firewall settings. My internet connection is working good and to check firewall settings i disabled it but still no programs or applications are installing. Also updates of some programs are not working. (I am using eset security). PLEASE HELP!!

I also tried that cmd scanning process but nothing happened.
All apps says check your internet connection and firewall settings.