(Note: for personal reasons posting may be light to non-existent for a while.)
You have a laptop. A good one, only two years old, and mostly working fine. Now, unfortunately, the laptop fan is — not broken, exactly, but sometimes it doesn't spin up when it should. Maybe the bearings are clogged, the motor may be going bad or perhaps a temperature sensor is malfunctioning.
The reason doesn't really matter — when the fails your laptop runs hot. Really hot. Even a slight extra load, such as watching a Youtube movie, is enough for it to slowly overheat and grind to a halt. It happens increasingly often, and it's becoming difficult to even use the machine by now. You need to do something.
What do you do? You could bring it to a repair center and have them fix it. But the machine is two years old and out of warranty. You're probably within a year from a new laptop anyhow, so a possibly expensive repair doesn't strike you as a great idea. And you depend on the machine every day, so you'd need to find and set up a replacement computer for a couple of weeks while it is in for repairs. Serious money. Major hassle.
You could open it up and hope to find some obvious flaw such as clogged-up dust or a loose cable. But you've already dusted the fan from the outside, these machines are difficult to open without special tools, and integrated laptop motherboards leave very little scope for home repairs. You're far more likely to break something else than to fix anything.
Or, you could take a junk-drawer cooling fan1, a left-over cellphone USB cable, a soldering iron and liberal amounts of gaffers tape:
USB ports give you 5 volts and 100mA of power for low-power devices. The fan I found draws 0.4 watts at 5 volts, or 80mA — nicely within the low-power limit. Solder the leads red-to-red and black-to-black, then use tape or heat-shrink tubing to isolate the connections (remember to thread the tubing on the leads before you solder... I always do that).
Gaffers tape works great both to hold the fan and to create a flexible, pliable enclosure to fit onto the air exhaust on the side. Gaffers tape is wonderful stuff — it cuts without tools, it's strong and flexible, and the glue doesn't leave any residue. A roll is pretty expensive but it lasts for years at home.
The result? My laptop idles at 75-80° without the fan, and will soon hit critical temperatures with any extra load. With this fix the machine stays between 55-60° in normal use and will remain below 80° even when I run 3-D applications or do intensive image processing. It's not completely silent, but the sound is so soft and muted — the tape dampens any vibrations — that I soon forget it's even there.
It's a hack. But when I can ill afford the time and money to repair or replace the computer, this hack solves my problem at no cost and with minimal effort.
We often underestimate the utility of the hack, the kludge, the temporary patch. It's not as good as a permanent fix, but often it doesn't need to be. If this hack keeps my machine running fine until it's time to replace it, then it's just as good as a real repair. Better, as it took less than an hour instead of many days or even weeks.
"Everything worth doing is not worth doing well", as a wise man put it. "'Perfect' is the enemy of 'good enough'", said another. Words of wisdom.
#1 Aren't you happy you saved that fan a few years ago? All that junk really does come in handy from time to time, no matter what other family members may say.