Free computer hardware tutorials

Computer Troubleshooting Tutorial

Troubleshooting computers can be a little frustrating and a little tricky. With so many parts and software installed, any number of things can go wrong. But when (not if) something happens, this is the best opportunity for you to learn-of course provided that you have a few basics under your belt. Nothing beats experience. The more you do it, the better you become, and the more your confidence grows. And the best part, you will save yourself a lot of money.

There are many things that can go wrong with a computer. Here, I try to cover the basics to get you going in the right direction.

Well let's start with an important tip: When troubleshooting computers always start with the simple stuff. By that I mean there's a tendency to assume that when something happens it's always due to a major problem, when all it could be is a loose cable or something else minor. I have been guilty of this myself. Check the easy things first!!!

Now the real challenge is deciding whether a symptom is hardware or software related. A lot of times this comes through trial and error. Don't be afraid of misdiagnosing a problem. It's going to happen. Just keep at it.

Issues During POST:
When you power on your system, the power supply sends a signal to the CPU, which receives instructions to go to the BIOS to start the boot process. Part of this process is the POST (Power On Self Test). Problems arising at this stage are almost always hardware. During the POST, devices are found and checked for errors. If everything is fine the motherboard speaker will usually sound a single, short beep and move on to loading the operating system. If something occurs you will hear some type of beep or see an error message on the screen. BIOS manufacturers have different beep codes so you will have to know which BIOS your system is using. Phoenix and AMI are the two primary makers. Award BIOS was bought out by Phoenix in 1998. You can find the type of BIOS you have by either turning on your computer (assuming of course it comes on) and looking at the top left of the screen, opening the case and looking at the BIOS chip, consulting the motherboard manufacturer or the company that built your computer.

Whichever BIOS you have, if the beep code indicates a memory or video card problem the usual solution is to check to see if they are fully seated in their slots or to replace the part. If using built-in video then it could be the motherboard. If it's a CPU beep code your processor might be overheating. Some BIOS setups are set to shut the computer down if the processor is too hot. A malfunctioning processor fan can could be the culprit. Turn off the computer and remove the case door. Turn the computer back on and see if the fan is working or running slowly. If it's the fan, replace it. If not, remove the processor and see if there's any physical damage to it. Keep in mind that you will not always see physical damage on a bad CPU.

If you don't hear a beep at all, more than likely it's a failing power supply or motherboard.

Devices Not Listed in BIOS:
Immediately after the POST is performed information about your computer is listed on the screen, including your drives. If you don't see a drive listed, go back and make sure they are installed properly and that cables are firmly connected.

BIOS hardware list

No Operating System Found or Similar Message:
After the POST and listed information the BIOS checks the boot device for the master boot record (MBR), which tells where the operating system (OS) is. A drive set to boot with no operating system will produce an error, so make sure your system is set to boot from the right device. Go into CMOS and look under the BOOT menu to see if the proper boot order is listed. (Again, depending on the BIOS, there are various ways to enter CMOS. It's listed at the bottom of the screen soon after you turn on the computer. Most of the time it's by pressing DEL, F1, or F2). In many cases the DVD drive is first on the list followed by the hard drive(s). That's OK. If the DVD drive is empty, the BIOS skips it and starts looking at the hard drives. If there is a non-bootable DVD in the drive, remove it. Your boot drive should be the first option or second (If DVD drive is first). Once found, the OS begins to load.

Viewing the boot order in CMOS

Another cause for this message is that the master boot record itself can become corrupted. There is a link to a quick tutorial on how to fix a damaged MBR with an XP or Vista CD located here.

Computer is Slow:
A computer that runs at a snail's pace is quite annoying, especially when you have a lot of work to get done. Fortunately, many of the common causes are easily fixable.

A slow running computer is often due to viruses and spyware which are discussed below. Another cause can be programs running in the background. Many times when installing new software, by default they're designed to run when Windows starts. You can look in the tray at the bottom right of the screen to see all the installed software that's running. You can usually stop these from starting with Windows by either right-clicking on the program's icon in the tray and select its properties or options and choose not to have it begin at startup. Or open the entire program and go to the options/properties menu.

Another way to prevent programs from running at startup is to run msconfig.

To open msconfig in XP click start, run, type msconfig. In Vista click start, type msconfig in the "start search" text box right above the task bar (the program icon should appear in the white area above the text box), then either double click the icon or press enter. Go to the startup tab. There you will see the same programs that are in your tray. You have the choice of disabling them all (not wise, there is certain software that needs to run when Windows starts such as anti-virus) or individually selecting the ones you don't want to start by unchecking the box next to them. After making your selection(s) click apply. Your choices will go into effect the next time you start your computer.


Another common reason for a slow computer is not having enough RAM. Installing more can often help the problem.

Viruses and spyware can not only slow down your computer, they can render it unusable. Furthermore, certain types of viruses and spyware can transmit your personal information to the attackers. You should always have antivirus running on your system. If you are looking for a good free option, I recommend Avast.

Limited Hard Drive Space:
After a long period of time, most of our hard drives contain data we no longer need or that is left over by software not completely uninstalled eventually leading to a messy drive. Given the size of modern hard drives, this is rarely an issue anymore. In any event, if you are a clean freak like me, you may want to periodically clean house. Windows built-in Disk Cleaner tool is a good way to get rid of unwanted files, although there's plenty of other software available too. And of course, you can always add an additional hard drive if you need more storage space.

To open Disk Cleanup in XP or Vista click start -> Programs -> Accessories -> System Tools -> Disk Cleanup and follow the instructions.

Fragmented Hard Drive:
When a hard drive is brand new and you begin installing software or saving data, Windows tries to keep all the individual files intact, resulting in them being read extremely fast. But after a while you start deleting things. Well, each time something is deleted, it leaves "gaps" in your drive. Then when another program is installed or data saved, individual files are broken up and placed in these gaps all over the drive. This is what is known as a fragmented hard drive. When opening a file or program, the operating system has to scan the entire drive to find parts of files and put them back together, reducing read time. This why it can seem like forever for a file to open.

Defragmenting a hard drive is easy with Windows Disk Defragmenter. It scans your drive for split up files and reassembles them. To open In XP or Vista click -> Start -> Accessories -> System Tools -> Disk Defragmenter. Before using Disk Defragmenter I would suggest running Disk Cleanup first to eliminate unwanted data. As with Disk Cleanup, there are many other 3rd party defragmenting programs available.


Non-Working Devices/Device Not Recognized:
If a device has stopped functioning or isn't recognized by Windows, remember to first check the simple things. Make sure cables and power are plugged in. With an internal component, turn off and unplug the machine. Remove the case door and make sure cables are firmly connected to the device and that add-on cards are seated in their slots. If all is OK, there may be a device driver issue. Device drivers are little pieces of software that allow hardware to work. Reinstall the device driver or download the latest version. Either go the manufacturer of the device or the company where you bought your computer. If still no success try uninstalling and reinstalling the device.

If the above doesn't produce any results, it is probably the device itself.

Problems After Installing New Software or Device Driver:
Of course you should first uninstall the software or driver. Or use System Restore to return your system to a previous working state. To open System System Restore in XP or Vista click Start -> Programs -> Accessories -> System Tools -> System Restore.

System Restore

There are times when new programs might freeze up your system. In this case try to see if you can boot to Safe Mode and then perform a restore. Safe Mode only loads the very basic devices and drivers needed for your system. To get to Safe Mode restart your system. When it begins to boot, continuously press the F8 key. A menu should appear that looks similar to the one on the left. Choose Safe Mode and press enter. After Windows loads you should get the screen on the right with a black desktop. Start System Restore like described above.

Safe Mode

No Power:
The main culprit is usually the power supply unit (PSU). Make sure the power cord is securely plugged into the supply and the wall outlet. If so, you can buy a tester to see whether your PSU is putting out enough voltage.

Another cause could be a malfunctioning device. Turn off the computer and disconnect all devices. Reinstall each device one by one, turning on the computer after each device. Should your system not come on after installing a particular component, replace it.

If your system doesn't come on after reinstalling every device, you may have a motherboard or CPU problem.

Spontaneous Reboots:
A computer that reboots often (while you're in Windows or other operating system) is another indication of a bad power supply. See the first couple of sentences under No Power above.

Time Keeps Changing:
If you constantly have to set the time/date clock, that's the main symptom of a bad CMOS battery. Replace it. But just like any other battery it has to be the same size. Look at the number on your battery and buy one with the same number.