A user is receiving repeated pop-up advertising messages while browsing the internet. A malware scan is unable to locate the source of an infection. Which of the following should the technician check next?

Windows updates are essential for maintaining system security and performance, but they do not directly address issues related to pop-up advertisements. While keeping the operating system updated is important, it is unlikely to resolve problems caused by browser-specific components such as plug-ins or extensions.

DNS settings control how domain names are resolved to IP addresses and can affect internet connectivity but do not usually cause pop-up advertisements. Issues with DNS might lead to browsing errors or redirects, but they are not typically linked to the appearance of persistent advertising messages.

The certificate store holds security certificates used to establish secure connections but is unrelated to pop-up advertisements. While issues in the certificate store can lead to security warnings or blocked sites, they do not contribute to the presence of adware or unwanted ads in a browser.