The first step in troubleshooting any network connectivity issue is to identify the scope and source of the problem. The technician should check if any infrastructure changes have been made during the user's absence, such as updates, patches, configuration changes, or hardware replacements. These changes could affect the network settings, firewall rules, permissions, or compatibility of the user's device or the server. The technician should also verify if other users or devices can access the server or if the problem is isolated to the user's device. By determining if any infrastructure changes have been made, the technician can narrow down the possible causes and formulate a theory to test.
References
Chapter 5: Hardware and Network Troubleshooting
How to fix HTTP 500 internal server error?
Remote desktop connection: An internal error has occurred

NFC (Near Field Communication) is the technology used for contactless payment features on mobile payment devices. If a mobile payment device is having issues with its contactless payment feature and is not detecting payment options, it is most likely due to an issue with the NFC functionality of the device.
The contactless payment feature on a mobile payment device uses NFC (Near Field Communication) to detect payment options. If the device is not detecting payment options, the issue may be related to a problem with the NFC feature. References: https://www.techopedia.com/definition/31790/near-field-communication-nfc

Running the printer's alignment process is the first step that a technician should do to fix the shadowing problem on the printouts. Shadowing is a print quality issue that occurs when the printer prints a faint duplicate image of the original text or graphics, usually slightly offset from the original position. This can be caused by a misalignment of the printhead, which is the part of the printer that sprays ink onto the paper. The printer's alignment process is a procedure that adjusts the position and angle of the printhead to ensure that the ink is applied accurately and evenly on the paper. The printer's alignment process can be performed from the printer's menu, the printer's software, or the printer's maintenance tool, depending on the model and type of the printer.
The other options are not the best solutions for this problem. Reseating the new ink cartridges may not solve the shadowing issue, unless the cartridges are not properly installed or recognized by the printer. However, this is unlikely to be the case, as the printer would usually display an error message or refuse to print if the cartridges are not compatible or inserted correctly. Replacing the fuser assembly or installing the maintenance kit are more drastic and expensive measures that are usually done when the printer has more serious problems, such as paper jams, smearing, streaking, or fading. The fuser assembly is the part of the printer that heats and melts the toner onto the paper, and the maintenance kit is a set of components that need to be replaced periodically to keep the printer in good condition. These parts are not directly related to the shadowing issue, and replacing them may not fix the problem.
References:
* CompTIA A+ Certification Exam Core 1 Objectives1
* The Official CompTIA A+ Core 1 Student Guide (Exam 220-1101) eBook2
* How to Fix Shadow Printing on My Canon Printer?3
* Fixing A Printer That Creates Shadow Images On Printouts4

DNS stands for Domain Name System, and it is a network service that translates human-readable names (such as www.google.com) into numerical IP addresses (such as 172.217.14.206) that identify the location of the web servers on the internet. DNS also allows reverse lookup, which means finding the domain name associated with a given IP address. DNS servers are responsible for maintaining a database of domain names and their corresponding IP addresses, and responding to queries from clients who want to resolve a name to an address or vice versa12.
DHCP stands for Dynamic Host Configuration Protocol, and it is a network service that automatically assigns IP addresses and other network configuration parameters (such as subnet mask, default gateway, DNS server, etc.) to devices that join a network. DHCP servers are responsible for managing a pool of IP addresses and leasing them to clients for a specified duration. DHCP servers also renew or release the IP addresses when the lease expires or the client disconnects from the network34.
The difference between DNS and DHCP is that DNS is used for address translation, which means converting domain names to IP addresses and vice versa, while DHCP is used for IP address assignment, which means providing IP addresses and other network settings to devices that need to communicate on a network.
References:
* DNS Configuration - CompTIA A+ 220-1101 - 2.6
* DHCP Configuration - CompTIA A+ 220-1101 - 2.6 - Professor Messer IT Certification Training Courses
* CompTIA A+ 220-1101 - 2.6 - Professor Messer IT Certification ...
* Courses for CompTIA A+: 220-1101: CompTIA A+ (Core 1) - Skillsoft

Upgrading all workstations and providing a virtual environment for the legacy software is the best option, as it allows the engineering department to continue using the vital software while also upgrading to the latest version of Windows. This also ensures that the rest of the organization can take advantage of the latest software and security features.