PC Troubleshooting Guide: Find Out Which Piece of Hardware Is Malfunctioning in Your PC

Your PC can be a very complex machine, especially if you don’t have a handle on how its hardware works. There’s a lot of stuff that can go wrong, and there’s no definitive way to find out which hardware is at fault without putting on a little elbow grease and getting creative. This PC troubleshooting guide is meant to make this process easier by pointing you in the right direction. I’ll list the most troublesome pieces of hardware and list the most common problems that each of them causes. Let’s get started!

Before You Start

Before assuming that a piece of hardware is causing problems in your computer, make sure that the socket on your wall is working and all cables are properly connected both outside and inside the computer. Check for loose connections and ensure that you’re not attempting to use the computer at a voltage that’s not recommended.

1. The Power Supply


The computer cannot turn on without it. The power supply is the piece of your computer that gives it life. It’s directly connected to the motherboard and many other components of the computer such as your DVD drive and your hard disk drive. Here’s a list of common problems you can experience with your power supply:

Computer doesn’t turn on

The power supply provides the power to your computer, so if it cannot be powered on, the power supply could highly be the culprit. The best way to determine whether the power supply’s causing this is to listen for any sounds coming in from the computer. If you don’t hear any fans whirring, then your power supply might be faulty. If the only noise coming from the computer is from the power supply, perhaps its fans are the only things working or maybe it’s not properly connected to the motherboard.

DVD drive or hard drive doesn’t function

A peripheral drive may cease to function when its connection to the power supply comes loose. Check the power cables connecting to each to see if they’re fastened properly. If you can wiggle them, they’re not connected well enough.

Insufficient power

If you have just added a new component to the computer and the computer doesn’t turn on, perhaps the power supply isn’t providing sufficient power to compensate for the new hardware. Remove the hardware and turn the computer on again. If it’s working, you need a more powerful power supply before adding this hardware.

Faulty power supplies often occur after short circuits and power surges. Make sure you connect your computer to a surge protector on a grounded socket to prevent these incidents.

2. The Memory (RAM)


Computers store components of their operating systems and running programs/services through the random access memory (RAM) cards. If they’re malfunctioning, you may experience the following symptoms:

Computer doesn’t display anything when turned on (accompanied by a weird beep sequence/lack of beeps).

If your computer normally beeps once when it turns on, listen for two or more beeps, or no beeps at all. For a more detailed overview on beep codes, you can visit this page. If you get strange beeps, assume it has something to do with memory if you didn’t just add hardware.

Excessive blue screen errors.

Blue screen errors often happen when there’s something wrong with your memory. This isn’t always a rule. However, if they’re very random and aren’t generally reproducible, then you’ve probably got a memory problem. If you can reproduce the issue by clicking something, it’s probably that “something’s” fault.

Unacceptably slow performance.

If your computer is taking long to open programs, first open your task manager to make sure that your RAM is not full. If it’s full, try closing programs that use a lot of RAM. If that’s not enough, you need more RAM, assuming that you’re not also infected by malware (I suggest you try also scanning for malware using some software like malwarebytes before jumping to conclusions). Slow performance is often the result of using the minimal amount of RAM necessary to run a computer. You often need at least twice (sometimes three times) as much RAM than what the minimum system requirements for an operating system tell you to get.

One good tool for testing your memory (just to make sure it’s malfunctioning) is memtest86+. We’ve covered this little handy tool many times because it works. If you see problems in your RAM while testing it (a big red label on the screen), then replace it. If there are no problems during at least three passes of the test, then you’re likely to have another issue.

3. Input Devices


Sometimes, keyboards and mice can do pretty weird stuff! Here are some problems caused by your input devices:

Erratic computer behavior (known as the ‘computer poltergeist’). 

One time, I had a faulty keyboard that randomly sent a key sequence to the computer that caused it to open windows insanely, open and close the Start menu, and sometimes shut down the computer on its own. It is by far the weirdest keyboard malfunction that I have ever seen. When the computer starts acting weird like that, unplug the keyboard. If it settles down, then the keyboard was at fault. Replace it with a spare.

Battery discharge.

If your keyboard and mouse are wireless, don’t forget to replace/recharge the batteries! This is a common oversight since batteries last so long nowadays. We often take this for granted and forget that this might be the reason there’s no registered input.

4. The Hard Drive


Hard drives are the snails of the computing world since they contain moving parts. They store all of the permanent data on your computer. All of it. Here’s a list of symptoms that your hard drive is causing problems:

File transfer gets stuck

This is often a sign of a bad drive sector. Run “chkdsk /r” in the command line to try fixing this.

Small rhythmic clicking noise when computer first turns on

This might be a sign of a head crash and is a very dangerous premonition to the death of your hard drive. Make sure you make a full backup of your system if you still can. This drive’s about to go bust!

Complete and sudden loss of all data despite no format

If you didn’t format your hard drive and you lost all your data, you’re likely dealing with a corrupted partition and file system. This doesn’t happen very often, but when it does, the effects are devastating. To solve this, try using software like Recuva.

Very slow performance

If your computer takes a long time to boot and start programs (and, you’ve already tried singling out your RAM as the issue), then you have a slow hard drive. Defragmenting it (search “defragmenter” in your Start menu) is one of the first things you should try. If that doesn’t solve anything, you might need a new hard drive, assuming your computer is free of malware.

5. The CPU

The CPU can be a very troublesome piece of hardware because of the amount of heat it emanates and the amount of responsibility it’s given. After all, the CPU is the heart of your computer. Let’s look at symptoms of CPU issues:

Frequent and sudden random shutdowns.

If you’re not getting a blue screen, but the computer’s always just shutting down on you without any prior warning, this is a telltale sign that your CPU is overheating. Either get a better cooling fan for it, improve the airflow inside your computer, or replace the CPU and hope that the next one has a better stock cooler. Sometimes, thermal grease might be wearing out on the CPU, and there are also cases where the CPU is overheating because many of its transistors have already reached the end of their lifespans. You often end up getting a new computer long before a CPU would need to be replaced for this reason, though.

Slow performance

If your CPU is not old, you can forget about this. If you bought a CPU that was released within the last year, you’re not likely to have performance issues because of it. Anything older, and you should check the task manager. Assuming that you’re not infected with malware, a 100% CPU usage with a couple of light programs open should indicate that you need a new CPU. Of course, it could also be a program’s fault. If one program is using 100% of the CPU consistently, you really need to close it. After that, see how the computer performs. If you’re still getting very slow performance (and 100% CPU usage across the board), then you really need to replace this piece of hardware.

Computer won’t display anything

Again, like with RAM, a failed CPU will cause your computer to completely stop in its tracks when turning on. Unfortunately, there’s no easy way to determine whether the CPU’s at fault. You should first try replacing your RAM with some spare cards to see if they could be the culprit. If you still get the same problems, you either must replace the CPU, or you may even have to replace the motherboard.

6. The Motherboard


The motherboard is tied closely to the CPU, RAM, and power supply. If you can’t seem to find any problems with your RAM and CPU, the motherboard may be at fault. Unfortunately, this is a very complex piece of hardware to test, as it’s the nerve center of the computer. If you’re unsure whether a problem pertains to the motherboard or another piece, mount that piece on another computer to see if it works. There’s a lot of trial and error involved, and a guide like this is very useful in such times. More often than not, though, the CPU or RAM are at fault. The motherboard seldom has problems. You often end up buying a new motherboard anyway before the old one has run enough time to fail.

Computer Support Engineer by Big Stock Photo.

Miguel Leiva-Gomez
Miguel Leiva-Gomez

Miguel has been a business growth and technology expert for more than a decade and has written software for even longer. From his little castle in Romania, he presents cold and analytical perspectives to things that affect the tech world.

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