Memory fan does not seem to be working, what can be causing this?

Hi guys, i purchased an Alienware Aurora desktop last year (early December). Here are the specs in case they are needed.

I7 920 (stock speeds)

6G ram (1033mhz)

Ati 5870

Anyway, this problem originally came to my attention when i noticed that my computer seems to be louder than usual, though i could not tell if that was simply me overreacting or if something was wrong, perhaps due to a fan not working. I checked my command center and noticed that everything was working, except for the System fan, which was at 0 RPM. I turned off my computer and opened it up to make sure that the 4pin connector was plugged into the Sys_Fan slot, which it was. I then tried unplugging it and holding the power down for about 30 seconds, then turning it back on, which also did nothing. That was yesterday. Fast forward to today, and i try something new. I opened up the side and turned my computer on to see if i could see if any of the fans were not spinning. Will i did, except not the ones that i was expecting.

The memory fan mounted on the top of the computer (upside down) that is connected to the "Mem_Fan" is not spinning, and neither (though I'm not sure if it's supposed to) is the big fan on the rear of the computer, where the liquid cooling is connected to. To make things more interesting, i checked my command center while i was doing this and the system fan now works fine, idling at roughly 1100RPM. Another reason why i suspect that something is wrong is because the computer does not make the same sound when it boots up as it did anymore. Usually, the fans would be very loud when i boot it up (and my monitor off) before going very quiet the instant my monitor turns on and the bios screen loads, and it would do this every single time. Now, the fans continue to be loud even after my monitor turns on and stops when i am at the login screen. However, if i restart it after i booted it up for the first time, it follows the regular sound pattern that it did in the past, save for an extra sound that it did not make at the login screen.

So here is my general question. Is the memory fan just not supposed to be working, or what? I don't see it anywhere in the command center, but i don't understand why a fan would exist without working. Also, is the giant fan (I'm pretty sure its a fan) in the rear that the liquid cooling is attached to supposed to spin, or not? Please help me out as this uncertainty is driving me mad.

Cliffs: Memory fan and Rear fan (that the liquid cooling is attached to) are not spinning. Is that normal, or not?