Many people face computer problems every day. Some computer problems are easy to fix, but may go undiagnosed. This wikiHow teaches you how to diagnose common computer problems on a Windows computer.
Steps

Step 1. Verify that the cables and components are connected correctly
This is especially important if you have just powered up your computer. Open the computer and make sure all cables, RAM chips, video card, sound card, network card, and other components are firmly connected to the motherboard.

Step 2. Review the POST
POST stands for "Boot Self Test". This is part of a computer's startup program that is used to diagnose the keyboard, random access memory (RAM), disk drives, and other hardware to ensure that they are working properly. If POST detects a hardware error, it will display an error text message on the screen or a series of short and long beeps.
If you get an error message while starting your computer, type the exact error message into a Google search to find more information about the error. Use your mobile phone or other computer, if necessary. If you hear a series of beeps as the computer boots, make a note of the pattern and use this website to see what error the pattern indicates

Step 3. Check the loading time of the operating system
The time it takes an operating system to load when a computer is turned on depends a lot on the hardware of the computer. If you find that the operating system is taking much longer to load than normal, this may indicate a problem with the hard drive that is preventing the computer from retrieving information from it.

Step 4. Check for problems with the graphics
If the computer is able to boot properly, but you notice problems with the graphics, this may indicate failures with the graphics card drivers or hardware. If you suspect that there might be a problem with your graphics card, you should first update your graphics card drivers. If the problem still persists, you can download software to test the graphics card.

Step 5. Check for hardware problems
Many computer problems are caused by hardware failures or problems with hardware drivers. Windows will generally notify you of devices that have a problem. You can also use Device Manager to check the status of different hardware devices. Double-click a category in Device Manager to display all the devices in that category. Then double click on a specific device. Any errors with the device will be displayed in the "Device Status" box of the "General" tab. Check all devices. Use the following steps to open Device Manager:
- Click on the Windows "Start" menu in the lower left corner.
- Type Control Panel.
- Double-click on the Control Panel in the Windows "Start" menu.
- Click on Hardware and sound.
- Click on Device administrator under "Devices and Printers".

Step 6. Check if there is any recently installed software
Some software programs may require more resources than the system can provide. Most likely, if a problem starts after the software starts, it is the software that is causing it. If the problem appears right at boot, it may be caused by software that starts automatically at boot. Uninstall any recently installed programs and see if the problem continues. You may also want to limit the number of startup programs.

Step 7. Check the consumption of RAM and CPU
If the computer is slow or slow, it is good practice to see if a program is consuming more resources than the computer can provide. An easy way to check this is to use the Task Manager, right-click the taskbar at the bottom of the screen and click Task Manager. Click on the tab Processes. Click on CPU to display a graph of current CPU usage. Click on Memory to see a graph of RAM consumption.
- If your computer's CPU graph is between 80% and 100% most of the time, you may be able to swap your computer's processor for a more powerful one.
- If your computer is using too much memory, close all unnecessary browser programs and tabs and see if your computer's performance improves. Limit the amount of multitasking you do on your computer. If your computer doesn't have enough memory to perform basic operations, some computers allow you to purchase and install more RAM.

Step 8. Listen to the computer
If the hard drive is scratching or making loud noises, turn off the computer and have a professional diagnose the hard drive. Also, listen to the CPU fan. If the fan is blowing hard, this could mean that the CPU is getting too hot because it is working hard.
If you suspect you have a damaged hard drive, be sure to back up all important data on the drive immediately and turn off your computer. Every time you boot a computer with a damaged hard drive, it will be damaged even more. If you can't back up your data, remove the hard drive and take it to a professional for recovery

Step 9. Run a virus and malware scan
Performance problems can be caused by malware on the computer. Running a virus scan can unearth any problems. Use a reputable antivirus program that is updated frequently, such as Norton, McAfee, or Malwarebytes.

Step 10. Review the problem in safe mode
As a last resort, review the problem in safe mode. If the problem persists in safe mode, the operating system is almost certainly the culprit. You may need to reinstall Windows.
Advice
- If you are not comfortable diagnosing or repairing a computer problem, it is best to take the computer to a licensed technician and have it repaired for a moderate fee.
- These procedures will begin to narrow down common problems, but to find a specific problem, you may have to use specialized tools or techniques.
Warnings
- Do not try to repair problems unless you are sure you know what you are doing.
- Always consult a competent computer technician, whether you are troubleshooting the problem yourself or under supervision.