Dell Inspiron 1525 Fan Rattling Noise

The fan in my 1525 inspiron laptop recently started giving off this annoying rattling sound. I've looked it up elsewhere, but the most common solution I came across was to clean out the fan. I cleaned the fan area thoroughly, following the instructions stated the inspiron manual found on this site, but the rattle it still there.

Anyone else experienced the same problem? or have any idea what else I could do to fix it.

Thanks in advance.