Computer maintenance is the practice of keeping computers in a good state of repair. A computer containing accumulated dust and debris may not run properly.
Dust and debris will accumulate as a result of air cooling. Any filters used to mitigate this need. If the cooling system is not filtered then
The crumbs, dust, and other particulate that fall between the keys and the walls of the air, are then loosened by spraying pressurized air in the keyboard, then removed with a low-pressure vacuum cleaner. A plastic-cleaning agent applied to the surface of the keys with a cloth is used to remove the accumulation of oil and dirt from repeated contact with a user’s fingertips. If this is not sufficient for a more severely dirty keyboard, the keys are physically removed for more focused individual cleaning, or for better access to the beneath area. Finally, the surface is wiped with a disinfectant.
A monitor displays information in visual form, using text and graphics. The portion of the monitor that displays the information is called the screen. Like a television screen, a computer screen can show still or moving pictures and It’s a part of Output Devices. There are two basic types of monitors: CRT (cathode ray tube) and liquid crystal display monitors. Both types produce sharp images, but LCD monitors have the advantage of being much thinner and lighter. CRT monitors, however, are more affordable.
Fingerprints, water spots, and dust screen for the screen type (CRT, LCD, etc.). A general plastic-cleaning agent is used on the outer casing, which requires a gentle gentle cleanser but may need more focused attention to unusual buildups of dust, grime, pen marks, etc. idiosyncratic to the user and environment.
The top surface of the mouse is with a plastic cleanser to remove the dirt that accumulates from the hand, as on the keyboard. The bottom surface is also cleaned to ensure that it can slide freely. If it is a mechanical mouse , the trackball is taken out, not only to clean the ball itself, but to scrape dirt from the runners that sense the ball’s movement and can become jittery or stuck if impeded by grime.
Tower / desktop unit
Internal components accumulated by the airflow maintained by fans to keep the PC from overheating. A soft brush can remove loose dirt; the remainder is dislodged with compressed air and removed with a low-pressure vacuum. The case is wiped down with a cleaning agent. A pressurized blower or gas duster can remove dust that can not be reached with a brush. 
Important data stored on computers may be copied and archived securely so, in the event of failure, the data and systems may be reconstructed. When Major Maintenance Such As patching is Performed, a backup is recommended as the first step in box the update fails and reversion is required.
Disk cleanup can be performed as regular maintenance to remove these. Files may become fragmented and so slow the performance of the computer. Disk defragmentation can be performed to combine these fragments and so improve performance.
In the United States, the Digital Millennium Copyright Act is specifically exempt from computer-maintenance activities, so it can be made in the course of maintenance that they are destroyed afterwards. 
Operating-system files such as Windows registry may require maintenance. A utility such as a registry cleaner may be used for this. Also inbuilt Disk defragmenter will also help.
Software packages and operating systems may require regular updates to correct software bugs and to address security weaknesses.
Maintaining security involves vulnerability management and installation and proper operation of antivirus software .
- Preventive maintenance
- Jump up^ Acosta, Jeremy. “Basic Computer Maintenance” . Games and Gears .
- Jump up^ Kent D. Stuckey (1996), Internet and online law , pp. 6-47