How Can I Shed a Persistent Web Site ?

I'm having trouble with a "political" web site (they sell drugs as it turns out) that I can't get rid of.

I keep getting a pop-up with a rectangle showing a choice between "leave" or "stay".

If I click on"leave" their home page is briefly seen, but then it leaves.

If I click on "stay" I'm shown a very long web page, at the end of which I'm given only the choice to "Buy". But I can still leave that page.

Malwarebytes Anti-Malware and Avast Antivirus do not find a problem.

Except for the annoyance factor, my computer seems to otherwise work normally.

Can someone help me please?

Which browser are you using?

If your browser gives you the option, install an ad blocker such as uBlockOrigin. If you are still using Adobe Flash, get rid of it. At a minimum, disable it. Same for Microsoft's Silverlight.

Check your Windows programs list and see if something installed itself in your operating system (OS). If so, uninstall it.

Browser I'm currently using is Opera.

I installed uBlockOrigin for Opera. That app appears very useful, but doesn't remove my problem web site.

I uninstalled Adobe Flash. No effect.

Where do I find "Windows programs list" ?

Start>>>Control Panel>>>Programs and Features (or Programs>>>Uninstall a program)

Do you get this problem whenever surfing the net, or only at a specific site?

Hi Scuzzy. Sometimes the Internet is maddening. After three days of hanging around, today my intrusive web site suddenly disappeared and hasn't come back yet. Since this happened well after I applied the measures you recommended, I guess I'll never know what ended my problem. Thanks for your suggestions.

Maddening is a good word to describe it.  I hope the problem is resolved for you, however it happened.