just uninstall and reinstall it ,for example How to uninstall ZoneAlarm completely from XP/Vista/Win 7

You just need to go to the toolbar on your browser and click the small arrow next to the Icon. Click on the help option and then click Uninstall. It will do it from there

maybe  you infect   staging.ktsart.com virus

What is staging.ktsart.com?Staging.ktsart.com is a website browser hijacker. Once infected with Staging.ktsart.com, it displays a windows require you input logon username and password.

1Open an Internet browser window. In this example, Microsoft Internet Explorer is used.

2Right click once in a blank area of your toolbar, and select "Toolbar Options". In this example, the Google toolbar and pop up blocker are used, but this process will work the same with any pop-up blocker

Read more: How to Get Rid of a Pop-Up Blocker