Internet Explorer: In your browser window's toolbar, select Tools > Internet Options. In the Internet Options window, select the Privacy tab. Click the Advanced button. In the Advanced Privacy Settings window, ensure that the check boxes marked "Override automatic cookie handling" and "Always allow session cookies" are checked. Click the OK button in this window, then the Apply button and the OK button in the previous window.

Mozilla Firefox: In your browser window's toolbar, select Tools > Options. In the left bar of the Options window, click the Privacy icon. In the main window, expand Cookies. Ensure that the check box marked "Enable cookies" is checked. Whichever sub-setting you choose should be fine.

Opera: In your browser window's toolbar, select Tools > Preferences. In the left bar of the preferences window, select Privacy. Ensure that the check box marked "Enable cookies" is checked, and that either "Accept all cookies" or "Let me decide every time I receive one" is selected in the drop down box labeled "Normal cookies".