Is it safe to remove cookies from my computer.Suppose i remove the Yahoo cookie, what effect will it have.Can anyone explain the full role of cookies.Thanks

   Cookies are mainly there for your convenience.  The cookie tells the website things about you that it learned when you were at that website before.  It keeps that information on your computer.  That way the next time that you visit that website it will remember, for example, your name and greet you by your name.
   This board uses cookies to remember your login and password, that way when you come to this board it can sign you in automatically.  If you delete the cookie, you will have to enter your login and password.
   A cookie does NOT (and cannot) go into your computer, hunt out private information and send that to someone else or share it with other websites.
   The only disadvantage with cookies is that if you do not go back to a website, you really don't need its cookie and so its cookie is just sitting there on your computer wasting space.
   Removing all of the cookies will mean that you will be treated by each website as if you were visiting it for the first time.

thanks but suppose an undesirable site opens automatically whenever i log on and that sites cookie is there in my computer, in such case  wether removal of the cookie will help to prevent the site from opening.

   No, it does not work that way.  It is not the cookie that causes the undesirable site to open automatically.  A cookie is only used once the website is open and is only used on that website.  Removing the cookie will not keep it from opening.  But if you want to remove the cookie, go ahead and remove it.

thanks a lot.s