A technician is troubleshooting a user's PC that is displaying pop-up windows advertising free software...

The symptoms described—pop-up ads promoting unwanted software and memory errors—are classic signs of spyware or adware infection. The technician’s next best step is to install antispyware software designed to detect and remove such threats. While antivirus software is important, antispyware specifically targets the kind of adware causing the pop-ups and performance issues. Reimaging is a last resort after malware removal attempts fail. Disabling the pop-up blocker or upgrading the browser would not address the root infection and may worsen the problem by allowing more unwanted pop-ups. This matches Core 2 security and troubleshooting objectives, emphasizing malware removal tools and remediation steps.