First off, you should know better than to double post.
It is a common problem for A8N-SLIs to have their chipset fan die on them. If you want to keep your warranty, you best be RMAing that, as replacing that fan/heatsink will void your warranty.
I did a bit of reading and it seems that the Zalman NB47 chipset fan/heatsink is a mighty good replacement.
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