What is the first thing to do when a new system has been assembled?

Okay, here's information about the first steps to take after assembling a new computer system, formatted in Markdown with WikiWhat links:

After assembling a new computer system, the very first thing you should do is perform a visual inspection. Carefully examine all components and connections inside the case.

Specifically, check for:

• Loose Cables: Make sure all power cables (ATX, EPS, PCIe, SATA) and data cables (SATA, NVMe) are firmly seated in their respective connectors. Even if you think you plugged them in tightly during assembly, vibrations during transport or slight misalignments can cause them to loosen.
• Component Seating: Verify that the CPU, RAM modules, GPU (graphics card), and any other expansion cards are fully seated in their slots. Reseat them if necessary.
• Fan Obstructions: Ensure that no cables are obstructing any fans (CPU cooler fan, case fans, GPU fans). Obstructed fans can lead to overheating.
• Stray Screws or Metal: Look for any stray screws, standoffs, or small pieces of metal that may have fallen into the case during assembly. These could cause a short circuit.
• Cooler Mounting: Check that the CPU cooler is securely mounted to the CPU and that there is good contact. Proper cooling is essential for initial boot-up. If you used thermal paste, make sure it was applied correctly.
• Power Supply Switch: Confirm that the power supply (PSU) switch on the back of the case is set to the "on" (typically marked as "I") position.

Once you've completed the internal visual inspection, double-check the external connections (monitor, keyboard, mouse) before proceeding to the next step, which is the initial power-on test. Doing this thorough visual check can prevent potential damage or frustration later on.