[ElDiabloConCaca]

It doesn't sound like a cooling fan fault -- the fans seem to be operating normally. The speed of them is software-controlled, so the operating system will determine what speed to spin them at. However, your picture depics a "kernel panic" of sorts, and when this happens, the operating system is basically kaput and not controlling the hardware anymore. It's truly locked up. Therefore, the fans will spin at maximum speed because the unit is powered up, but no software is telling the fans to spin slow, so they're spinning at maximum speed as a precaution.

Some causes of kernel panics are bad RAM (some people experience them when they upgrade their RAM), a faulty operating system install, incompatible add-on hardware, or a big, non-user-serviceable hardwre problem with some part of the machine.

First thing I would do is to remove any added-on RAM. Return the machine to an "as-stock-as-possible" configuration and see if the kernel panics continue (by the way, I see no harm in turning the machine on again. This is assuming that you do have the mandatory backup of all your important stuff -- if not, then any data corruption that results from turning the machine on again is in your hands).

Failing that, remove USB devices -- they're notorious (especially USB hubs) for causing problems with kernel panics and sleep mode.

If you've returned the machine to a stock configuration and are still experiencing kernel panics, I would next suspect the operating system. Since you do regular backups, wiping the drive and starting fresh should be no problem -- pop in the Mac OS X Install CD/DVD and format and reinstall OS X, afterward using Software Update to update the operating system and software to the latest versions.

If kernel panics continue at this point, something most likely out of your hands is happening and would probably require an Apple Authorized Repair Center. One thing you can do to try and narrow down the problem is to run the Apple Hardware Diagnostics CD... when you do run the tests, run them in a loop (one after another, over and over) -- major hardware problems are usually not found the first pass through the diagnostic. Jot any pertinent information down, and if a piece of hardware comes up faulty, you can present this information to the repair tech.