CompTIA A+ Hardware and Network Troubleshooting Summary

The CompTIA troubleshooting steps start with identifying the problem: talk to the user, find out what changed, try to repeat the problem, and back up data before making changes. Only then does the technician form and test a theory.

Wrong choices

• Test the theory to determine the cause: Testing comes after a theory has been formed.
• Document findings, actions, and outcomes: Documenting is the last step, after the problem is fixed and verified.
• Establish a theory of probable cause: A theory comes second, after the technician has gathered information about the problem.

A small coin battery on the motherboard keeps the firmware clock and settings when the PC has no power. When that battery dies, the clock and settings reset every time the PC is unplugged. Replacing the battery fixes it.

Wrong choices

• The hard drive is failing: A failing drive causes slow access, errors, or noises. It does not reset the clock or firmware settings.
• The power supply is failing: A failing power supply causes shutdowns or no power, not lost settings after the PC is unplugged.
• The time zone is set wrong in Windows: A wrong time zone gives a time that is off by a set amount every day. It does not reset the firmware settings.

A PC that turns off after working hard for a while, then starts fine once it cools, is most likely overheating. Dust-clogged heatsinks, failed fans, or dried-out thermal paste are common causes. The PC shuts itself off to protect the parts.

Wrong choices

• The CMOS battery: A dead CMOS battery resets the clock and settings. It does not cause shutdowns under load.
• The network cable: A loose network cable drops the internet connection but does not shut the PC off.
• The amount of free disk space: Low disk space slows the PC down but does not make it turn off.

The final troubleshooting step is to document what was found, what was done, and what the result was. Good notes help the next technician solve the same problem faster.

Wrong choices

• Establish a theory of probable cause: Forming a theory happens near the start of troubleshooting.
• Identify the problem: Identifying the problem is the first step, not the last.
• Test the theory to determine the cause: Testing the theory happens earlier, before the fix is made.

The steps in order are: identify the problem, establish a theory, test the theory, establish a plan and implement the fix, verify full system functionality, and document. So after forming a theory, the technician tests it to see whether it is the real cause.

Wrong choices

• Verify full system functionality: Verifying comes after the fix has been put in place.
• Establish a plan of action and implement the solution: The plan comes after the theory has been tested and confirmed.
• Document findings, actions, and outcomes: Documenting is the final step.

Clicking or grinding from a hard drive usually means it is failing mechanically. The drive could stop working at any time, so the first job is to copy the user's data to a safe place. Then the drive can be replaced.

Wrong choices

• Install the latest operating system updates: Updates will not fix a drive that is physically failing.
• Ignore the sound because hard drives always click: A repeated clicking sound is a common warning that a hard drive is failing.
• Run a disk defragmenter to speed it up: Defragmenting puts heavy work on a drive that may be failing and could finish it off before the data is saved.

When a laser printer runs low on toner, there is not enough to cover the page, so everything prints light and faded. Replacing the toner cartridge is the usual fix.

Wrong choices

• The wrong printer driver is installed: A wrong driver usually prints strange characters or garbage, not evenly faded pages.
• The paper is jammed: A paper jam stops printing. It does not make pages faded.
• The fuser is failing: A failing fuser makes toner smear or rub off. The print is not usually evenly faded.

The link light shows whether there is a physical connection. If it is off, start with the simplest cause: a loose, unplugged, or damaged cable, or a problem at the wall jack or switch port. Checking the obvious first saves time.

Wrong choices

• The motherboard, by replacing it: Replacing the motherboard is costly and should come only after simple checks like the cable.
• The operating system, by reinstalling it: Reinstalling the operating system is drastic and does not address a missing physical link.
• The DNS server settings: DNS problems stop names from working but do not turn off the link light.

If testing does not confirm the theory, the technician goes back and forms a new theory. If the technician has run out of ideas or lacks the access or skills needed, the problem should be escalated to someone who can help.

Wrong choices

• Replace the motherboard to be safe: Replacing parts without a confirmed cause wastes time and money.
• Document the problem as solved and close the ticket: The problem is not solved, so closing the ticket would leave the user without a working PC.
• Put the fix in place anyway: The test showed the theory was wrong, so a fix based on it would not solve the problem.

When a separate graphics card is installed, many systems turn off the motherboard's built-in video. If the monitor cable is still in the motherboard's port, the screen stays black. Moving the cable to the graphics card's port is the simple fix.

Wrong choices

• The hard drive has failed: A failed drive would still show startup screens or an error message. The monitor would not stay black.
• The new graphics card needs a driver before any picture appears: Even without a driver, a basic picture appears during startup. A totally black screen points to the connection.
• The CMOS battery has died: A dead CMOS battery causes clock and settings problems, not a black screen right after a graphics card install.