CPU Fan is Loud, but the Temperature is OK (I Think)

I recently find that my CPU fan is getting louder and louder. It is now so loud that I bother to type up a question on it.

The first thing I check is the temperature using Core Temp, it seems that the temperature is OK for Intel Core 2 Duo E8400 ( I think):

But still, besides being annoying, I am not sure whether there is any other side effect of a loud fan, such as causing damages to my hardware. So my question is, is there anyway I can verify the correctness of the reading above, or is there any other thing I can do to reduce the noise level of the fan?

Edit: I have clean the dust on the fan ( there isn't a lot), and log into the BIOS. The BOIS stats are:

1. System temperature: 37


2. CPU temperature: 47


3. CPU fan speed: 1044 rpm


4. System fan 2 speed: 0 rpm


5. Power fan speed: 0 rpm


6. System fan 1 speed: 0 rpm.

Now, I wonder is it that my fan is failing? Because it seems that system fan and power fan are all 0 rpm.