Computer running slow who's guilty

Our school office has a computer recently running slowly, they want me this "expert" to help them diagnose the computer, so that the computer to restore the original speed. The author went after a look, indeed very slowly, than before the author to help them just installed the system after the speed is much slower, the author first thought is that the computer may be affected by the virus, because the recent campus intranet virus activity rampant, and the computer installed virus firewall for a long time did not upgrade, so I took out just made, Contains the latest virus library files Jiangmin dos antivirus companion u disk, start antivirus, found C, D, E, F disk have a lot of viruses, and can be removed or deleted. When I restart the computer and feel the computer is still so slow, it seems that the slow is not caused by the virus.

is the operating system with too much time in the garbage file or the registry too messy caused it? The quickest way to solve this problem is to restore the system, in the knowledge of C disk (System disk) No important things, under the premise of the author with a U disk restart the computer, into the DOS system, with ghost restore the operating system. Before the author restores the system, will feel the operation of the machine obviously accelerated, but this time is still very slow, it seems that the problem is not in the software. The author found a screwdriver, cut off the power, turned on the computer, saw the inside is full of dust, and the CPU fan and heatsink are covered with dust, start the computer to observe the speed of the fan, see the speed is very slow, as the old cow pull broken car, I removed the CPU heatsink and fan, by the hand touch the CPU, the feeling of abnormally high temperature, it seems , the heat dissipation of the CPU has a great problem, so the author with a brush to remove the heat sink and fan dust, and found some lubricating oil on the fan shaft, and also cleaned the motherboard and graphics and other accessories on the dust, load the CPU fan, restart the computer, see the CPU fan speed significantly faster, Feel the speed of computer operation is obviously accelerated, after 1 hours of running test, the computer running speed did not drop significantly. The author asked the office staff, is not a recent period of time, the computer has just started running speed can also, after a period of time running more and more slowly, they say this is the case. Now I conclude that the computer is running slowly, because the CPU temperature is too high, the CPU temperature is too high due to the problem of heat dissipation. And the heat dissipation problem is caused by dust.

The impact of dust on the computer is a problem that can not be underestimated, especially in public places to run the computer, because people walk frequently in public places, and sweeping frequent, environmental dust, the computer is easy to accumulate ash, in the previous physics and chemistry teaching and teaching office computer, has appeared because of computer internal ash too much Causes the computer to be unstable and frequently freezes the phenomenon.