Take out the graphics card and install a spare one. Some cheapie PCI card from a decade ago will be good enough.

Indeed.

Do your hear any beeps and/or the harddrives booting? If you do hear this, then it's probably the video card.
If you don't hear this, then it's probably the mainboard or ram, or the CPU (although CPU's don't fail often)

Its probably the graphics card. It must have failed and it must not be taking in the power it gets to its chip making the fan spin extreamlly fast. Which will be killing the fan. Of cours it could still be the mb if its onboard video also I cannot stress enouigh do you hear the hdd booting.

<div class='quotetop'>QUOTE(Burger Meister @ Aug 15 2006, 04:35 PM) [snapback]248705[/snapback]</div>Do you get a beep from the speaker? I can be helpful if you get a certain signal from it.

And WHAT fan runs so loud? the case fan, the cpu fan or the graphic card fan?
Sometimes you have really simple solutions to complex problems. ^_^

[quote]

Like smashing the computer..?
Smashing the user is generally more effective though.

You may have a short in the power supply. That's the only thing I can think of to make the fan run that loudly.