You can prevent individual sites from using cookies by following the instructions relating to your browser below.
Click the menu icon and select Settings. On the page that appears, scroll down to the bottom and click Show advanced settings. Click on the Content settings... button in the Privacy section. In the pop-up that appears, click Manage exceptions... in the Cookies section. Enter the site's domain name in the text field, change the drop-down menu to Block, and click Finished twice to close the two windows.
While viewing the site, right-click on the page and select View Page Info from the context menu. In the window that appears, click on the Permission tab. In the Set Cookies section, uncheck the Use Default box and select Block. Close the window.
Select Internet options from the Tools menu. In the window that appears, click on the Privacy tab and click the Sites button. In the window that appears, enter the site's domain name in the text field and click Block. Click OK twice to close the two windows.
While viewing the site, click the Opera button in the top-left of the window, then select Settings, Quick Preferences, and finally Edit Site Preferences.... In the window that appears, click on the Cookies tab, select Never accept cookies, and click OK.
Please check your browser's help file for information on managing cookies.