Loud fan, no boot

[mhergenr]

Hi,

I currently have an IBM Thinkcentre with Ubuntu Linux (the latest version). I recently hibernated it and haven't used it for a week. All of a sudden, when I turn it on, it does not boot/start with BIOS, nor does the connected monitor even wake up (I've tested the monitor and it works fine). What's more: the front fan all of a sudden runs at full speed and is really loud. I haven't the faintest idea of what's gone wrong. I've tried:

-doing an F1 startup diagnostic - no beeps
-removing and reinserting the RAM cards after cleaning

Neither has worked. The front and back LED's are both lit fine. I've looked inside, and I haven't seen a blown capacitor anywhere. I've provided a picture link - the fan on the left side of the picture is the problem. http://imgur.com/OVPWw

Thank you very much for any help I can get with this!

[Transfusion]

The front fan is spinning at top speed because the BIOS hasn't loaded and therefore ACPI hasn't kicked in, so the full 12V are being supplied to the fan. 

Have you tried resetting CMOS and booting with only the essentials installed (Power supply, Motherboard, CPU, and only 1 stick of RAM, no extraneous fans or drives or expansion cards inserted)?

[mhergenr]

Haven't tried that - will do so now. Thanks!

[mhergenr]

So I first tried resetting CMOS by pulling out the battery, waiting ten minutes, and putting it back in. It did load the BIOS, and while the fan didn't run at 100%, it was still pretty heavy. On a list of BIOS info, it did mention a fan failure - I'm thinking this is the problem? What is unexpected to me was that even after resetting, my boot password still existed. However, I'm not sure what to do next - I got to the BIOS menu, didn't change anything and elected to continue w/o saving. From there, nothing happened...

[mhergenr]

Here is a link to what came up when I started the computer. Are there any BIOS settings I need to look at in particular? I'm new to this part, and I don't really have any personal settings that I changed manually apart from the boot password that still exists.
http://imgur.com/U0FDh

(sorry about double posting)

EDIT: I was able to restart again without touching the BIOS settings and was able to fully log in. Thank you for the help - your tip was right on the money! Thank you so much! (the only problem remaining is a fan failure - I assume I should replace it?)

[Transfusion]

Yeah try replacing the fan with another one, it may just be that the RPM monitor on the fan has failed, thus causing the motherboard to not be able to POST at the beginning. No biggie.