Lesson 2. Common Problems on Desktops

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There are two types of common computer problems; hardware and software. Most people are familiar with software related computer problems because they present an error message identifying a specific program as the cause. Viruses are another common computer problem associated with software.


Common computer problems caused by hardware are more difficult for the average user to identify. Hardware components like the motherboard, hard drive and power supply unit (PSU) are a much bigger cause of common computer problems than most people realize.

Problems Caused By VirusesThe most common computer problems today are viruses. They can affect hard drives, flash drives, MP3 players, cell phones and almost any removable media that connects to a computer. MalwareBytes is an antivirus program good at removing viruses if it is run soon after the infection occurs. If a virus is on the computer for very long, it is often faster and more effective to reformat the computer and do a complete reinstall of the operating system and software applications.


The best way to deal with viruses is to prevent them from infecting the computer in the first place. Installing a quality antivirus program like Avira is always a good idea. Keeping the antivirus program up to date and running a virus scan regularly will make it much more difficult for a virus to infect the computer and cause problems.

Problems Caused by Soldering Defects

The motherboard and graphics card are the two most likely pieces of hardware to create common computer problems because of soldering defects. Both use a component called a metal-oxide-semiconductor field-effect transistor (MOSFET). If the MOSFET is not properly soldered to the graphics card or motherboard, the system will become very unstable.

Figure 1: A faulty MOSFET on a motherboard.

The ball grid array (BGA) is another area where poor soldering can cause a component to fail. This is frequently the cause of graphics card failures. The graphics card overheats and stops sending images to the monitor causing it to shut down.

Faulty Capacitors

The PSU is one of the most important components in a desktop computer because it connects directly to most of the other components. If the PSU is faulty, all of the components it supplies power to are at risk and the potential for common computer problems increases significantly.

Figure 2: The inside view of a power supply unit.

The capacitors are the most common part of the PSU to fail. As they age, the capacitors dry out and lose their ability to regulate the voltage output effectively. A qualified technician will be required to replace faulty capacitors. Often the best course of action is to replace the PSU instead of trying to fix it.

Figure 3: A digital oscilloscope.

The best way to test capacitors is with an oscilloscope. If the PSU is functioning correctly, the line will be flat, as it appears in Figure 4. If the capacitors are faulty, there will be spikes making the line uneven.

Figure 4: An oscillogram of PSU +5 volts rail.

It is often possible to identify faulty capacitors just by looking at them. If the capacitors are a little bumpy, then they are faulty. Figure 5 shows faulty capacitors in a PSU. Motherboards also have several capacitors. Figure 6 shows faulty capacitors on a motherboard.

Figure 5: Faulty capacitors in a power supply unit.

Figure 6: Faulty capacitors on a motherboard.

Problems Caused by Overheating

The central processing unit (CPU) is the piece of computer hardware most susceptible to damage from overheating. A large heat sink helps keep the CPU cool. In order for the heat sink to work, it needs to have good contact with the CPU. A thin layer of thermal paste ensures good contact. After a few years, the thermal paste can dry out and will actually keep the heat in rather than allowing it to dissipate. The heat sink can also become clogged with dust and become less effective. It is recommended to clean the inside of the computer with compressed air and replace the thermal paste once a year. Arctic Silver is one of the most trusted brands of computer paste on the market.


Graphics cards are also very susceptible to overheating. When this happens, the monitor will not display anything. This happens randomly when the computer is in use and is much more frequent when used for graphics intensive activities like playing computer games.

Figure 7: A graphic card designed for gaming.

A faulty capacitor or BGA soldering can cause overheating. Faulty MOSFET soldering is more common on graphics cards designed for gaming.

Figure 8: A faulty MOSFET on a graphics card.

Common Hard Drive Problems

Most manufacturers design their hard drives to last for decades. Unfortunately, there is a very good chance they will start failing after only three years. This is usually a result of the manufacturing process. Production of hard drives and other components is happing at a faster and faster rate. For example, a production plant that produced 300 hard drives each day five years ago might turn out 1,000 today. The increased speed of production results in a decrease in quality. This is especially true with the cheaper models.


All of the components in a computer work together and often power fluctuation trigger hard drive failures. The hard drive needs the power supply to stay constant. When it fluctuates, there is a high potential for damage to occur. The PSU is designed prevent power fluctuations to the various computer components. An oscilloscope can easily identify a PSU that is allowing power fluctuations to happen.

USB Ports Causing Computer Problems

It is often very difficult to identify damaged USB ports just by looking at them. When there is damage to the USB ports, the computer will suddenly shut down and restart. These symptoms often lead people to conclude there is a problem with the PSU because the computer can function fine for days with faulty USB ports. The most common USB ports to fail are located n the front of the computer casing.


Most of the common computer problems caused by hardware issues are difficult for the average user to identify. A trained computer technician with the right tools and knowledge can quickly identify the cause and fix it before the computer experiences more damage.


Back from Common Computer Problems on Desktops to troubleshooting computer problems

Back from Common Computer Problems on Desktops to Home

About basic computer troubleshooting

Easy diagnosing computer problems

Tips on computer hardware troubleshooting

How to troubleshoot computer monitor

Computer network troubleshooting at home



Computer Repair User Guide

Troubleshooting Computer Problems

How To Fix Computer Problems

Maintenance And Repair

Fix A Slow Computer

Remove Virus

Network Repair

Hard Drive Repair

Computer Repair Tools

Computer Help

Computer Repair Course

 Computer Repair Lessons Continued: 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120


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