Explanation
Virtual memory is a software-based memory management system that allows a computer to use hard disk storage space as RAM. This can be used to increase the total RAM in a system without upgrading the hardware. To set up virtual memory, the user should go to the System Properties window and select the Advanced tab. In the Performance section, click on the Settings button, which will open the Performance Options window. Then, click on the Advanced tab and click on the Change button in the Virtual memory section. Finally, select the option to Automatically manage paging file size for all drives, and then click OK to save the changes.

Explanation
Adjusting the lens is the best solution to improve image quality in a projector. The lens can become misaligned over time or during transportation, causing the image to appear fuzzy.

Explanation
DNS stands for Domain Name System and is a service that translates domain names (such as www.example.com) into IP addresses (such as 192.168.1.100) that computers can use to communicate over a network. If the DNS server is offline, users may not be able to access websites or other network resources by using their domain names, even if they are online and reachable by their IP addresses. The technician should check if the DNS server is running and configured correctly, or use an alternative DNS server if possible.
Reference: https://www.comptia.org/training/books/a-core-1-220-1101-study-guide (page 81)

Explanation
Cable internet service is delivered through coaxial cables that are shared among multiple customers in a neighborhood. This means that the bandwidth may vary depending on the network congestion. Fiber, NIC, and DSL are not copper-based or shared mediums.
Reference: CompTIA A+ Core 1 (220-1101) Certification Study Guide, page 28.

Explanation
The correct answer is B. Gather additional details.
According to the CompTIA troubleshooting process for the A+ certification exams1, the technician should gather additional details after testing a theory that is incorrect. This step helps to identify the problem more accurately and establish a new theory of probable cause. The other options are not appropriate for this stage of the troubleshooting process. Documenting the findings, escalating the problem, and identifying user changes are steps that should be done later in the process, after determining the cause and implementing a solution1.