✔ 最佳答案
If you confirm the sound came from back, it should be one of the following reasons:
(disconnect power supply before do the followings)
1. Dust in Case Cooling fan: open your case and you can clean them out. If your cooling fan is too old(say 1-2 years), you can add some lubricant(smoothing oil) to ensure it run smoothly without sound.
2. Dust in Power Supply fan : Use torch and point into the power supply, check if there is any dust or not. if yes, you can use vaccume cleaner to clean first and use tooth picker to pick the dust one by one(if they group together) carefully. Don't use too much force.
3. Cable over cooling fan : Open your case, connect power and turn your computer on, check if there is any cable is near cooling fan, fix and tight them properly.
4. Harddisk life(the sound should come from front) : Open your case, connect power and turn on PC, heard the sound source. If the sound is from Harddisk, it should be obvious.
No matter for what reason, you should clean your PC once for every 1-2 months, if you are a bit lazy, you can clean it once for every 4-6 months.
This depends on how dusty is your house.
