Explanation
Booting into safe mode and performing a malware scan are the steps that a technician should perform when troubleshooting an issue with pop-up advertising messages on a PC. Safe mode is a diagnostic mode that starts the PC with minimal drivers and services, which can prevent the pop-up malware from running. Malware scan is a tool that can detect and remove the pop-up malware, as well as prevent further infection or damage.
Investigating how the malware was installed, reinstalling the browser and restarting the machine are possible steps that can be done after booting into safe mode and performing a malware scan, depending on the situation and the results of the scan. Verified References: https://www.comptia.org/blog/how-to-boot-into-safe-mode
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