If your IBM ThinkPad laptop turns black and displays "fan error," this means your CPU fan malfunctioned. To fix the fan error, you must address the underlying cause. You can't just reboot the system and hope for the best. You must take this problem very seriously. Without a functioning fan, your computer's processor could overheat and become damaged in a matter of minutes. Fortunately, with some proactive fan cleaning, you can get the fan working again, resolving the error message and any potential processor damage.
Turn off your IBM ThinkPad.
Unplug your ThinkPad from the wall outlet. Remove the battery from the laptop.
Tilt the ThinkPad so you can see its left edge clearly. You will notice a series of small vents. These vents are used for CPU fan exhaust.
Dip a cotton swab in rubbing alcohol.
Swab away any external dust or dirt from the fan vents. Avoid pushing the cotton swab completely through the vents. Over time, a ThinkPad's fan vents can accumulate a lot of debris that is difficult to remove without an alcohol-based cleanser.
Blow compressed air into the vents to remove any remaining dust or blockage. Sometimes the fan stops working simply because of accumulated dusty buildup.
Plug in your ThinkPad, reattach the battery and boot up the system. If the fan is still not working, your computer will be unable to boot, displaying yet another "fan error" message. If the fan is not clogged, the fan error is due to fan assembly malfunction. According to Inside My Laptop, you will need to replace the entire fan assembly.
Things You'll Need
It's best to have a professional replace your fan assembly, as it requires removing the keyboard and accessing the computer's motherboard. The motherboard is the lifeblood of your computer; if you accidentally damage any microchips, circuits or wires connected to the motherboard, you can destroy the entire computer.