Noisy processor fan on Inspiron 1420

I have a noisy processor fan on my Dell Inspiron 1420 (laptop). Six months ago, I sent my laptop to Dell, where they replaced the Mother board (part # UX283), the Cooling pad (part # UX281) and the Thermal pad (part #UP755). IMO, they only needed to address the processor fan, but I don't fault them for being thorough. (They also replaced the LCD and keyboard lol!)

I have verified that I have the latest BIOS (in fact, I just reinstalled it). I ran a long diagnostic test after restarting the computer and pressing F12 when the Dell logo appeared. Frustratingly, the noise slowed (and then stopped) exactly when the diagnostic test slowed (and then stopped) the processor fan ... but the processor fan passed the diagnostic test with flying colors!

Notably, I have an NVIDIA GeForce Go 8400M GS with 128MB dedicated graphic memory (SKU 320-5496). However, mine does not appear to be subject to the recall (nor the associated class action suit).

I found an article on ZDNet UK by Greg Shultz that's dated June 3, 2003. It's called "Fix noisy computer fans with a drop of oil". It appears to contain a description of all the steps that I need to take to fix the fan except one: How do I get to the processor fan on a Dell Inspiron 1420?

My warranty has expired, and I don't won't to drop the $160 they're asking to renew it when all I need is a drop of oil. Besides, if experience is a guide, they won't be able to solve the problem for more than 6 months at a time anyway!

Can anyone advise me before I just start unscrewing the bottom of the Inspiron and "going at it"? The noise has become a big problem.

Thanks, Steve