●● 1. Software

● 1. Virus damage

Soon after the computer came into being, computer viruses came into being. When the network becomes the information artery of today's society, the spread of viruses is more convenient, so it also interferes with and destroys our normal work from time to time. A typical example is the "shock wave" virus that caused serious damage to computers around the world some time ago. When it breaks out, it will also prompt that the system will start automatically after 6 seconds. In fact, as early as the DOS era, many viruses can automatically restart your computer.

Whether it is virus damage or not, we can use the latest version of anti-virus software to carry out anti-virus, and generally we will find that viruses exist. Of course, there is another possibility that someone maliciously hacked into your computer when you were surfing the Internet and placed a Trojan horse program. This way, the other party can remotely control all the activities of your computer, including, of course, restarting your computer. For some Trojans, it is not easy to remove them, so it is better to reinstall the operating system.

● 2. System files are damaged

When system files are damaged, such as KERNEL32.DLL under Win2K, fonts under Win98 FONTS directory and other basic files during system operation are damaged, the system will be forced to restart when it is started. You can do an experiment and try to rename the FONTS in the WIN98 directory. When you turn it on again, our computer will start repeatedly.

for this kind of fault, because you can't access the normal desktop, you can only cover the installation or reinstall it.

● 3. Timing software or task planning software works

If you set up a restart or load some work programs in the "Planning Taskbar", the computer will start again when the timing comes. In this case, we can open the "startup" item and check whether there are any unfamiliar execution files or other scheduled work programs in it, and then screen them before starting up for inspection. Of course, we can also directly enter the "Msconfig" command in "Run" to select the startup item.

●● II. Hardware

● 1. Unstable mains voltage

The working voltage range of the switching power supply of general household computers is 17V-24 V. When the mains voltage is lower than 17 V, the computer will automatically restart or shut down. Because we sometimes don't feel the fluctuation of the mains voltage, we will mistakenly think that the computer automatically restarts for no reason.

solution: for areas with unstable power supply, we can purchase UPS power supply or 13-26 V wide switching power supply to ensure the stable operation of computers.

● 2. The quality of the plug-in strip or power socket is poor, and the contact is poor

Most power plug-in strips on the market are of poor quality, and the internal contacts are all welded by hand, and acid flux is often used, which will easily lead to solder joint oxidation leading to open circuit or leakage between live wire and zero wire in future use. Because of manual welding and the poor elasticity of the phosphor brass sheet, it is easy to lose elasticity in a short time, resulting in poor contact with the power plug of the host or monitor, resulting in a large contact resistance, which will lead to a large amount of heat when working for a long time, and then it will be manifested as the restart of the host or the flashing of the black screen of the monitor.

There is another wall socket that may be used in our home. Most of the wall sockets are not installed by professionals, so the wiring inside the socket is very nonstandard. Especially, if we often use high-power electric heaters, these sockets will easily lead to internal heating and oxidation, resulting in intermittent power failure, causing computer restart or display blinking.

Solution:

① Don't try to save money and buy cheap and inexpensive power strips. Buy some brand-name power strips, because they are automatically installed and crimped by machines without manual welding.

② as to whether it is a virtual connection in the wall socket, we can try changing the host computer into a wall socket to see if there is the same automatic restart problem.

● 3. The power of computer power supply is insufficient or its performance is poor

This situation is also quite common, especially when we add new equipment to our host, such as replacing high-grade graphics cards, adding burners and adding hard disks, which is easy to appear. When the host computer is working at full speed, such as running a large 3D game, burning at high speed or preparing to read a CD, when it is just started, double disk will copy data, which may cause power protection and stop output because of the instantaneous power shortage. However, when the power supply stops output, the load is reduced, and then the power supply is started again. Because the recovery time after protection is very short, the performance given to us is that the host automatically restarts.

there is another situation, that is, the performance of the switching power supply of the main engine is poor. Although the voltage is stable and within the normal allowable range, the main engine will often crash or restart because of the excessive harmonic content in its output power supply. In this case, it is normal when we use a multimeter to test its voltage. It is best to replace it with an excellent power supply.

solution: replace the high-quality and high-power computer power supply.

● 4. The mains plug of the main switch power supply is loose, poorly contacted and not plugged tightly

. Most of these cases will occur on DIY machines, and the power cord of the main switch power supply has not passed 3C certification and is not matched with the power socket. When we shake the table or touch the host, the host will automatically restart, which is usually accompanied by a slight "snapping" sound.

solution: replace the high-quality 3C certified power cord.

● 5. The power supply ATX2 socket of the motherboard has virtual welding and poor contact

This kind of fault is not common, but it does exist, mainly when the host is working normally, move the ATX2 pin plug left and right to see if the host will automatically restart. At the same time, check whether the reed inside the 2-pin power plug is oxidized, which can easily lead to large contact resistance and poor contact, causing the host to crash or restart. Sometimes it is necessary to check whether the connecting wires at the tail of the 2-pin plug are fastened.

Solution:

① If the solder joints of the main board are in virtual welding, just use the soldering iron to repair the welding directly. Note: When welding computer boards such as motherboards, hard disks and graphics cards, be sure to ground the soldering iron well or unplug the power plug during welding.

② If it is a power problem, it is best to replace it with a good one.

● 6. CPU problems

When some functional circuits inside the CPU are damaged and the secondary cache is damaged, the computer can also be started, and even enter the normal desktop for normal operation, but it will restart or crash when performing a special function, such as drawing tables, playing VCD and playing games.

solution: try to shield the second-level cache (L2) or the first-level cache (L1) in CMOS to see if the host can run normally; Or directly replace it with a good CPU. If it can run normally after shielding, it can still be used. Although it is slower, it will save money.

● 7. Memory problems

If a chip on the memory stick is not completely damaged, it is likely to pass the self-test (most of them are set with POST), but it will be restarted unexpectedly because of the function failure caused by the high heat of the memory during operation. Most of the time, when the memory is damaged, the opportunity will give an alarm, but after the memory is damaged, there are still faults of not giving an alarm and not powering up. It is best to use the elimination method, which can quickly determine the fault location.

● 8. optical drive problems

if the optical drive is damaged internally, it will also cause the host to start slowly or fail the self-test, or it may suddenly restart during work. In the latter case, if we replace the optical drive, it is likely that the power consumption of the optical drive is different. What you need to know is that although the ATPI interface of optical drives is the same, the pin definitions of different manufacturers are different. If there is something wrong with our hard disk cable, it may happen that there is no problem with one brand of optical drives, but it will not work with other brands of optical drives, which needs your attention.

● 9. There is something wrong with the quality of the RESET key

If the reset switch is damaged and the internal reed is always in the short-circuited position, the host computer will not be able to power on the self-test. However, when the elasticity of the RESET switch is weakened or the button on the chassis is not easy to bounce up, it will appear during use, because the chassis is occasionally touched or the host suddenly restarts under normal use. Therefore, when the RESET switch cannot be pressed freely, we must check it carefully, and it is best to replace it with a new RESET button switch or lubricate the external buttons of the chassis.

there is another case, because the insulation layer of the RESET switch lead in the chassis is peeled off too much during welding, and unpacking for many times during use will cause the RESET switch lead to be too close to cause collision, which will lead to the automatic restart of the host.

● 1. Automatically restart when connecting the network card or parallel port, serial port and USB interface to external devices

This situation is generally due to peripheral faults, such as the damage of the parallel port of the printer, the short circuit of one foot to the ground, the short circuit of the USB device to the ground, the nonstandard work of the network card, etc. When we use these devices, the computer will be restarted due to a sudden short circuit of power supply.

●● Third, other reasons

● 1. Poor heat dissipation or temperature measurement failure

The CPU has poor heat dissipation, and the common problems are that the fixing clip of the CPU radiator falls off, there are foreign objects between the CPU radiator and the CPU contact, and the radiator accumulates too much dust after the CPU fan is used for a long time. These situations will lead to poor heat dissipation of the CPU, and the accumulated temperature is too high and it will automatically restart.

there is also the damage of the temperature measuring probe under the CPU or the damage of the temperature measuring circuit inside the P4 CPU, and the BIOS on the motherboard has a BUG and the temperature measurement is not allowed under a certain special condition, which will cause the host to automatically restart protectively during work.

finally, the CPU protection temperature we set in CMOS is too low, which will also cause the host to automatically restart.

● 2. Fan speed measurement failure

When the speed measurement circuit of the CPU fan is damaged or the speed measurement line is intermittently broken, the motherboard will mistakenly think that the fan is stopped and automatically shut down or restart because it can't detect the speed of the fan, but we may see that the CPU fan rotates normally and the speed measurement is normal when checking.

● 3. Strong magnetic interference

Don't underestimate electromagnetic interference. Many times, our computer crashes and restarts are also caused by interference, which comes from the internal CPU fan, chassis fan, graphics card fan, graphics card, motherboard and hard disk, as well as external power lines, inverter air conditioners and even large equipment such as automobiles. If the jamming performance of our host is poor or the shielding is poor, the host will restart unexpectedly or crash frequently.