Precautions for purchasing second-hand notebooks:

Step 1: Observe the shell of the notebook.

Check the appearance carefully to see if it has been disassembled or cracked. If you find this kind of problem, don't buy it at any price. But if it's just some minor scratches, it can also be considered, because for the sake of maneuverability, some small friction is inevitable. And buying a second-hand notebook computer depends on the thickness, size and weight, compared with similar second-hand notebooks. Who chooses depends on his actual needs.

Step 2: Observe and check your LCD screen carefully.

This is very important. As we all know, LCD screen is the most expensive part of notebook computer accessories, accounting for 20%~35% of the whole machine cost. Therefore, we should pay special attention to: 1, whether the screen is damaged, because the machine with traces will be used for a long time, and the refraction of light will seriously damage people's vision. It is not cost-effective to accidentally move back to the machine that affects vision. 2. Carefully observe the size and display effect of the display screen, and consider the display effect and size of the display screen in combination with the price. Of course, it can also be used to reduce the price. 3. Identify the color of the display screen in detail. In addition to observing whether the screen is sixteen-color, 256-color or sixteen-bit true color and 24-bit true color, we should also observe it obliquely from top to bottom, left and right. If you can accurately see any color on the screen, you can judge that it is true color. Otherwise, if the color can only be recognized by observing it directly, it is pseudo color. You can hold a high-priced and high-quality LCD monitor in the business office and put it next to the notebook you want to buy. Under the same interface, compare their brightness, contrast, reaction speed, visibility and other parameters. 4. Pay attention to the delay performance and brightness of the display. When choosing a liquid crystal display, the most important thing is its delay length. If the delay is too long, your eyes will feel very tired. At the same time, brightness is a weakness of LCD. Generally, the brightness of popular LCD is 200cd/㎡ (lumen), and displays below this brightness are not desirable. Also, when looking at brightness, don't just look at brightness, but look at it with contrast adjustment. Some liquid crystal displays have the same brightness no matter how they are adjusted. As a result, when the contrast is improved, it looks dazzling and uncomfortable. In short, the eyes look comfortable and beautiful. 5. Pay attention to the bad points of the LCD screen. The most common ones are white spots and black spots. When you buy it, you can use the following simple methods to identify it: the general method of identifying black spots is to turn the whole screen background into a white screen, so that black spots can't escape your eyes; White dots are just the opposite. Turn the screen background to black, and then the white dots will show their true colors! However, in addition to white and black dots, there are sometimes dots of other colors. At this time, consumers can establish a red, yellow and blue screen background for simple identification.

Step 3: Carefully identify and test the components of the notebook.

Carefully check the CPU, hard disk, memory and other components of the notebook computer. When buying, you'd better take apart the machine and see for yourself. In addition, we must be alert to the despicable practice of profiteers using second-hand notebooks to replace notebook CPU with desktop CPU. Because the CPU with the same frequency will not be noticed by ordinary users, but the CPU using desktop and notebook is completely different. Due to the problem of different calorific value, the heat emitted by CPU cannot be emitted in the notebook, which leads to the instability of the system. Therefore, in the process of purchasing, it is required to conduct on-site inspection of CPU as much as possible. As for the hard disk, because we can't know the advantages and disadvantages of the hard disk by visual inspection, we can only detect it by software. The detection software can be DM, Norton, etc. After scanning with DM and Norton, DM takes a long time and Norton takes a short time. The scanning process must be smooth and consistent. If any cluster takes too long, there must be something wrong. As for memory, the memory of second-hand notebooks ranges from 32M to 256M. Try to choose a memory larger than 64M, preferably above 128M. Memory is replenished when purchasing, because some laptops have special memory, which has been discontinued and cannot be replaced. In addition, other built-in devices, such as video cards and sound cards, should also be checked face to face.

Step 4: Check the interface of the second-hand notebook computer.

Because it is very necessary to have a complete interface. In today's notebook computers, with the popularization and application of external storage devices, USB interface has become a necessary device for desktop and notebook computers, and USB interface is a very important interface. Therefore, it is best to buy a second-hand laptop with USB interface. In addition, the infrared transceiver function is also an indispensable function of the notebook now. Moreover, when buying a second-hand notebook, an important purchase condition is to look at its internal power supply. External power supply is necessary, and it is absolutely impossible without battery, so the power supply mainly depends on the quality of the battery, that is, the service life of the battery. Second-hand goods, Ni-MH batteries usually last for one hour or two, and lithium-ion batteries can last for two hours. This is the most basic requirement, otherwise it will not be considered.

Step 5: Check the status of peripheral devices.

Check whether the keyboard, mouse, CD-ROM drive, floppy drive and modem are available and easy to use. Last time I saw the keyboard of a second-hand notebook in the second-hand market, it was shiny and badly worn. In that case, I don't need to buy it. It would be better to change the keyboard.