How to Block Cookies

hi i want to know is there any way to block cookies from specific websites.so tell me the way to block third-Party Cookies. i feel venerable to virus, and maleware so i think precaution must be taken. so please tell me how can i do that thank you.

for Internet Explorer 7
press Alt to get up the menu
click on Tools.
Then click Internet Options.
Slide the Privacy slider to the middle or higher.

Now the cookies that do not have a compact privacy policy will get blocks third-party at this level by IE

check this for opera setting to avoid Cookies

http://my.opera.com/dude09/blog/2008...-block-cookies

you can use Clear All History application which stops third party cookies.
• advanced scheduler to clear history automatically
• supports Internet Explorer, MSN Explorer, Firefox, Maxthon (MyIE2), Opera, Netscape, Mozilla
• clear browsing history
• clean search history
• clear index.dat files content
• delete index.dat files
• clean AutoComplete
• clear address bar history
• clear Toolbar search history
• clear cache (Temporary Internet Files)
• clean stored passwords
• delete cookies
• empty Windows Temporary Folders
• clear Recently opened documents list

in firefoxtry this to block sites, from setting cookies.
1. Open Firefox.
2. In the Toolbar, at the top, click Tools and select Options...
This will open the Options dialog box.
3. Click the Privacy icon, and select the Cookies tab.
4. Click the Exceptions button.
This will open the Exceptions - Cookies dialog box.
5. In the Address of web site: box, type in the URL of the site you want to Allow, Allow for Session, or Block cookies from.
6. Click the appropriate button:
Block - This will block cookies from the specific site.
Allow for Session - This will allow cookies from the specific site, but will delete them when you exit Firefox.
Allow - This will allow cookies from the specific site, to be stored on your computer.
7. When your done, click the Close button.