Ok, we're trying to nip this. Bill's trying to put a stop to the ads, but just in case, if you do get the popup again, it would help to get some information.
Step 1). Right click on the edge of the ad/ element.
Step 2). Click inspect element
Step 3). This opens the developer tools.
Step 4). In the top left (in chrome) there is a magnifying glass. Click the magnifying glass.
Step 5). Click the ad in question immediately after clicking the magnifying glass.
Step 6). Take a screen shot of the code in the developer tools which is highlighted.
In IE, I believe right-clicking on the ad and choosing Inspect Element will highlight the code needed.
On my Chrome, the instructions above didn't match.. it worked more like IE...
Firefox also is a right-click, Inspect
thanks for your help!