i have thinkcentre lenovo, the fan is so noisy so how can i reduce the noise of this fan?
That's a little vague, so it's difficult to trouble-shoot. Was it always loud? If not, use some canned air to blow off the dust and lubricate it. If that doesn't work, replace it with an aftermarket fan with a low decible rating. If it was always loud and it's just a cooling fan on the case (or even the CPU fan), you can also purchase an aftermarket replacement. If this the fan in your graphics card or something, it's a bit harder to remedy.