Strange Url's in ASP.NET site

My asp.net 4 website url format is http://www.somesite.com/ShowProduct.aspx?ID=3330

but it sometimes gets changed to

http://www.somesite.com/(S(ghtef0vy5fgfdjgdfgderd55)X(1))/ShowProduct.aspx?ID=3330

or

http://www.somesite.com/ShowProduct.aspx?ID=3330&AspxAutoDetectCookieSupport=3330

How can i prevent this. I want all url's to be of this format only

http://www.somesite.com/ShowProduct.aspx?ID=3330

UPDATE:

I just saw that I have 开发者_如何转开发three entries

<authentication mode="Forms">
            <forms cookieless="UseCookies" loginUrl="~/NoAccess.aspx" name="FORMAUTH"/>
        </authentication>

and

<sessionState cookieless="AutoDetect"/>

and

<anonymousIdentification cookieless="AutoDetect" enabled="false"/>

What disadvantage will it have if I remove cookieless. WIll it break earlier bookmarked urls? Also how should both the config entries be rewritten so that i use cookies?

You've got a config that looks like this:

<configuration>
   <system.web>
      <sessionState mode="InProc" cookieless="AutoDetect" timeout="20"/>
      </sessionState>
   </system.web>
</configuration>

What you want is to remove the "cookieless" attribute so it defaults to "UseCookies"

http://msdn.microsoft.com/en-us/library/h6bb9cz9.aspx

You need to check the membership cookie settings for browsers, try looking under

<authentication mode="Forms">
  <forms ...>

And make sure that you have cookies="userCookies" set.

This usually means you are using cookieless session storage, and ASP.net alters the url to keep track, see MSDN for appropriate web.config configuration.