We may have to buy a used notebook computer to save money. But it will be more expensive if you buy wrong one and you have to spent more money to fix it again. So before you buy a used laptop computer check few things and repeat same test several times.
1: Laptop Charging: Is your laptop charging properly? When your laptop is switched on unplug the power cable and plug it again. Check it carefully. If after re plug in its charging correctly go to the next step. Keep charging and shut down the notebook. After the laptop computer fully turned off check it. If its still charging the battery go to the next step. Now unplug the power cable again and keep the laptop off. Plug the power cable in again. And check if the battery is charging switch on the laptop again while charging. Till now you have checked four conditions of charging a laptop which are I) Connecting charger to a switched on laptop, II) Switch of laptop while charging and check after shutdown, III) After Turned of unplug charger and plug again, IV) Turn on while charging cable is plugged in and laptop is charging mode.
Please note that this is not only charging test, also check your laptop is switching on properly or not while charger is plugged in.
2: Battery health: In most case you may have no option for battery health meter. If the battery is removable take it to your hand and check the body of the battery. If the body became fatty its health is not good. If body is accurate set it again and check charging and discharging time for few minutes. While charging check how many minutes it take to increase the percentage of battery level. Again unplug the charger and check while discharging how many time it takes to decrease the percentage of battery level. If battery drains too fast it may not a good battery or the motherboard may have faults. Also if it takes long time to charging battery the battery health may not good.
3: Check Ports: Check USB and other ports are working properly or not. Some times USB may cannot transfer files properly. It may be very slow to transfer a file using USB port. Check other ports like external monitor port HDMI or VGA ports are working or not.
4: Check webcam: Sometime webcam may not work or it may be blurry or cloudy which may not usable at all.
5: Check sound: Play any music file or play a video file from youtube. Check sound quality from both speaker. Also check the built in mic is working or not for calling.
6: Check display: Check display from all possible angles. Check for any dead pixel or line/bar.Display may be tapped or tampered. Display also may be cloudy and backlight may come out directly. You may see the back reflector in any particular area of display if it is damaged. Check the display colour and brightness. Sometime display may be replaced with ordinary one. You may not get proper colour tone from a ordinary display. Find any other similar laptop to compare display if possible.
7: Check body fitness: Check the body fitness. Check all screw is connected properly and body is closed perfectly. Check any corner and body edge is damaged broken or tempered.
8: Check any heating issue: Check any over heating issue. If you found any over heating without any reason, it may not suitable for you.
9: Check WiFi: Check WiFi is working properly. Check WiFi bands also. Check wifi signal quality.
10: Check HDD performance: Is there any noise from HDD? If the laptop is using an old HDD you may hear HDD noise. Its a sign of weak HDD. It will definitely slow down your laptop. Or can crash anytime. Try to buy a laptop with SSD or nVME instead of HDD. SSD and nVME also may have internal problem which may crash your operating system.
11: Check RAM: Any 6th Gen or higher CPU use DDR4 RAM, it is not wise to buy any laptop older than DDR4. If RAM has any issue your system also may slow down or crashes frequently.
12: Check GFX problems: In most case the GPU of a notebook may not work properly if it has served hardly due to very high process like video rendering or gaming. You may sudden screen flickering after working several hours. Or it may start showing blue screen or small rectangles shapes if the GPU is not working properly.
13: Switching off automatically: Your laptop may shutdown suddenly or keep restarting. This problem may cause for RAM, HDD/SSD/nVme or any other hardware problem. If the reason is RAM/HDD/SSD you may change or replace it. But if it comes from CPU/GPU or motherboard it will be terrible for you. Sometimes any overheating issue may cause this.
14: Check cooling Fan: Check the cooling fan is working perfectly. If cooling fan cannot run properly it cannot reduce the CPU temperature which will slow down your laptop or even stop all operation.
