So what makes a laptop get hotter and noisier over the years? Is it just mileage (20 months in this case) or all the crap that's on it? In other words, can some "file cleaning" help? How exactly?
Or is this automatically a sign that the notebook has a problem with its fan? It did not shut down because of heat yet, mind you. In the current (weather-caused) heat wave it did almost burn my knees, though. When I closed a rather demanding program like Skype it calmed down a litte.

Now, a comp-illiterate friend recommended cooling pads, see German link below. Are those any good, helpful or necessary? They're not cheap, at least.

Any ideas?