At present, there are basically several computers in the home. Nowadays, computers are cheaper and more powerful. But with the popularity of computers, there are more and more problems with computers at home. Usually people only use computers, but when there are problems, they are usually helpless. In the end, you can only take it to the repair shop for repair, which is not only troublesome but also expensive. But sometimes there are some small failures in computer knowledge, so it doesn't need to be so troublesome. Today, Xiaobian will tell you the problems that will occur in the computer and the solutions. Next, let me give you a good introduction.

1、 Why the computer can't start

1. The system does not recognize the hard disk

This kind of fault is quite common, that is, you can't start from the hard disk, you can't enter the C disk from the a disk, and you can't find the existence of the hard disk by using the automatic monitoring function in CMOS. This kind of fault mostly occurs on the connecting cable or IDE port. The fault rate of the hard disk itself is very small. You can quickly find the fault by reinstating the hard disk cable or changing the IDE port and cable for replacement test. If the newly connected hard disk is not recognized, another common reason is the master-slave line on the hard disk. If the hard disk is connected to the master disk position of the IDE, the hard disk must jump to the master disk shape, and the hard disk cannot be detected due to jumper errors.

2. CMOS caused failure

Whether CMOS is correct or not directly affects the normal use of hard disk, which mainly refers to the type of hard disk. Fortunately, current machines support the function of "ide auto detect", which can automatically detect the type of hard disk. When a new hard disk is connected or replaced, the type should be reset through this function. Of course, some types of motherboards can automatically identify the type of hard disk. When the hard disk type is wrong, sometimes the system cannot be started at all, sometimes it can be started, but read-write errors will occur. For example, if the hard disk type in CMOS is smaller than the actual hard disk capacity, the sectors behind the hard disk will not be able to read and write. If it is in the multi partition state, individual partitions will be lost. There is another important reason for the failure. Because the current ide supports logical parameter types, the hard disk can adopt normal, LBA, large, etc. If the data is installed in the general mode and changed to other modes in CMOS, the read-write error fault of the hard disk will occur, because its physical geological mapping relationship has changed, and the original correct hard disk location will not be read.

3. Startup failure caused by main boot program

The main boot sector of the hard disk is the most sensitive part of the hard disk, and the main boot program is a part of it. This program is mainly used to detect the correctness of the hard disk partition, determine the active partition, and transfer the boot right to the DOS or other operating system of the active partition. This program is damaged and cannot be booted from the hard disk, but the hard disk can be read and written from the soft or optical area. The method to repair this fault is relatively simple, and it is most convenient to use fdisk of higher version DOS. When running with parameter /mbr, the main boot program of the hard disk will be directly replaced (rewritten). In fact, the main boot sector of the hard disk is established by this program, fdisk. Exe contains a complete hard disk master boot program. Although the DOS version is constantly updated, the main boot program of the hard disk has not changed from DOS 3. X up to now, there is a DOS of windos 95, so as long as you find a DOS boot disk to start the system and run this program, you can repair it. In addition, other tool software such as kv300 also has this function.

4. Boot failure of partition table error boot

Partition table error is a serious error of hard disk. Different degrees of error will cause different losses. If there is no active partition flag, the computer cannot start. However, after booting the system from the soft or optical area, you can read and write to the hard disk, which can be repaired by resetting the active partition through fdisk. If a partition type is wrong, it can cause the loss of a partition. The fourth byte of the partition table is the partition type value. The normal bootable basic DOS partition value greater than 32MB is 06, while the extended dos partition value is 05. If the basic DOS partition type is changed to 05, the system cannot be started, and the data in it cannot be read or written. If 06 is changed to a type that dos does not recognize, such as EFH, DOS believes that the changed partition is not a DOS partition, and of course it cannot be read or written. Many people use this type value to realize the encryption technology of a single partition. Restoring the original correct type value can restore the partition to normal. Other data in the partition table is used to record the start or end address of the partition. The damage of these data will cause the confusion or loss of the partition. Generally, manual recovery cannot be carried out. The only way is to rewrite the backed up partition table data, or obtain the partition table data from other hard disks of the same type and with the same partition status, otherwise other data will be permanently lost. When operating the main boot sector, you can use Nu and other tools and software, which is very convenient to operate. You can directly read, write or edit the main boot sector of the hard disk. Of course, you can also use debug to operate, but the operation is cumbersome and has certain risks.

5. Hard disk failure caused by partition valid flag error

There is also an important part in the main boot sector of the hard disk, that is, the last two bytes: 55aah, which is the valid flag of the sector. When starting from the hard disk, floppy disk or optical area, these two bytes will be detected. If they exist, it is considered that there is a hard disk, otherwise it will not recognize the hard disk. When booting from the hard disk with this flag, it will be transferred to ROM basic or prompted to put it into the floppy disk. Cannot transfer to hard disk when booting from floppy disk. Encryption technology available here for the entire hard disk. The debug method can be used for recovery processing. In addition, the DOS boot sector still has such a flag. When the DOS boot sector has no boot flag, the system startup will be displayed as "missing operating system". The main boot sector repair method can be adopted, but the address is different. The more convenient method is to use the following general repair method of DOS system.

2、 Why computers often crash

In the process of using the computer, we often encounter the crash, which is accompanied by the computer operating system. This has been the case since the beginning of the windows graphical operating system. Why can't it be solved all the time? That starts with the way windows works. Why should we emphasize the windows operating system? Because in addition to the windows operating system, there are several other operating systems, the most famous of which is UNIX. The operation interface of UNIX focuses on the command line interface, which will reduce many resources. The original intention of the windows operating system is to popularize, so a lot of work has been done on the graphical interface, so there are also some loopholes. In addition, the windows operating system uses the working mode of memory call, and there will be problems when calling, so it has been unable to solve some problems.

Some common crash failures are also caused by some hidden problems, improper settings and operations, or problems of the system itself or the hardware itself. Based on the principle of "software before hardware" to solve the fault, we will analyze it slowly from software fault to hardware fault.

The first system problem

The operating system is very important for the use of the whole computer, and the blue screen caused by system problems is generally caused by the damage of system files or the destruction of startup files. If the system file is damaged, you can find this file and copy it to the system. You can also use the command provided by the system to repair it, or use the command console to recover it. The specific recovery steps can be found in the system file loss fault analysis of this book for more detailed instructions.

The second software problem

The most frequently used is the application software. There is also a production problem with the application software, which is also produced by using tool software. In the process of artificial production, there are inevitably many loopholes or mistakes. For example, in the game, it is easy to crash when entering and exiting the game, because the game itself is also running in the way of memory call. During the call, the computer may crash due to the wrong operation or the wrong programming of the program itself. In this case, you can only reinstall the software or install the corresponding patch of the software.

The third software virus residue file

When the software is uninstalled and the virus is deleted or killed, some files will remain, such as historical files, DLLs and other files, and these files may also remain in the system's registration file. When used, they are equivalent to normal use, but these programs and viruses have disappeared. Therefore, when the system is called, it cannot find the program, which may form an dead cycle and cause a crash. Software and virus residue files may also cause crash, so when uninstalling and antivirus, you need to pay attention to whether to leave temporary files, historical files and files that have not been deleted in the files, which need to be deleted.

The fourth software is incompatible

Some software may conflict with other software. For example, anti-virus software, due to different anti-virus mechanisms, may have conflicts when using system permissions, or other software is the same. So the solution to this kind of file error is to uninstall and reinstall or delete it directly.