Start with running MBAM (the free version) from https://nl.malwarebytes.org/downloads/.
If that finds nothing, run the full scan of your own antivirus program.
If it only happens inside your browser (when you are visiting some page), check the add-ons to see if one of them is the culprit. Details depend on what browser you use (Internet Explorer, Firefox, Chrome, Opera).
Kees
A pop-up that redirected me to a new webpage occurred (it was the web page of hxxp://www.computer-restore.com) A pop-up box appeared saying I had been infected and it then gave me a phone number to call (866-915-6151). It is trusty? How can I do?

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