If this is the original fan, and there is no chance that it has been 
disconnected and then reconnected to the wrong fan header, and it is 
spinning normally, this is unusual that the motherboard would tell you that 
no CPU fan was detected.  Other than the motherboard being defective, the 
only other option I can think of is that sometimes an older fan may not spin 
up to its normal speed very quickly and the motherboard may fail to detect a 
running fan during the initial boot and therefore conclude that there is no 
fan connected.  I would think that you would be able to see that the fan is 
having trouble spinning up, when the computer is first started, if this was 
the case, however.

I take it that either the BIOS does not have a hardware monitoring section 
or the computer shuts down too quickly for you to have a chance to see what 
the motherboard's monitoring function might have to say about the CPU fan's 
rpm/speed.

John Sproule


Date:    Fri, 13 Aug 2010 16:59:09 +0300
From:    Romario chipo <[log in to unmask]>
Subject: Re: Fan cannot be detected

The fan has not been replaced before. The fan came with the machine
and it spins quite okay thats why I am amazed by this error message.

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