After my web site opens I get what appears to be an add on or pop up.

Hi jimw
 
Welcome to the Community Forums.
 
If the popup is appearing on all websites visited it sounds like you may have fallen foul of a PUA or Potentially Unwanted Application.
 
There is usually some indication of the source of the popup in the popup itself, as it is usually advertising something. Can you check and let us know any details related to the popups and their source?  That would help us to further advise you as to how to proceed.
 
Below is some generic information on PUAs that we give out.  It will help inform you of what they are and has some information of some generic steps that you can try/do to get rid of them. But what we really need is details on the source.
 
PUAs are very annoying at best in that they cause pop-ups, redirect your browser home page, and other behaviour that may slow down the computer and direct ads your way, but they are not actually doing anything bad like damaging files or stealing information. Often they are installed intentionally by you the user as browser add-ons for various tasks such as quick search tools. But they also come with the result of added annoying pop-ups and ads. Other times they 'piggy back' with other software that you installed, or try to 'sneak' onto your system entirely.
 
The key to avoiding them is to make sure that when downloading apps one does so from the author's own website or one that they have recommended, and not 3rd party downloading site.
 
WSA does detect and remove many PUA's, and more are being added, but WSA does not detect all of them. A simple browser add-on with PUA behaviour that is easy to identify and easy to remove is not likely to be detected and removed by WSA. Those that are intentionally difficult to locate and remove are. Please see THIS LINK for more information regarding Webroot's stance on these annoying programs.
 
If you feel or consider yourself technically proficient then you can try these steps to remove it from your system.
 
However, if that does not work or you do not feel technically capable then the best thing to do is to Open a Support Ticket & ask Webroot Support to take a look and remove these for you.  There is NO CHARGE for this for valid WSA license holder.
 
We await your feedback.
 
Regards, Baldrick
 

Not sure if this is the information you  need:
After my web site opens I get this pop up.  This is when my computer becomes very unstable (opening or trying to open
unwanted windows)  It is obvious this a porn popup. As I said this happens on any site I enter.
Webroot support has tried (taking control of my computer) to remove or correct the problem.
Since I am a novice I have no idea what to do.
Thanks for your help. 

Hi jimw
 
Thanks for the reply.
 
Unfortunately, I cannot see the image that you have posted (if you have posted one) due to the restrictions in place on this site re. new members and posting images.  Is there any way that you can provide some of the text/is there a specific .com reference as to the source. Anything like that would help.
 
Also, you say the Support have already tried to assist you?  I take it that if you are still posting on this then they have had no success...which is strange, and if that is the case then I would go back to Support and ask them to advise back as to what the issue is, etc. 
 
Please keep us posted on what they say as it is unusal that the are not able to resolve an issue with PUAs.
 
Regards, Baldrick