I wanna share my experience with my dv5-1124ca, i've had for nearly 3 years now. Since the day i got it, it always been at least warm, and the fan pretty noisy. A few days ago, i just couldn't take it anymore, it had gotten to a point where the fan noise was driving me crazy, the 84 degrees idling temperature killed 2 of my batteries, figured i'd stop being lazy, and open it up. The best decision i took concerning this laptop. First things first, the fan. I really suggest, to anyone who even hears his fan, to open up your laptop and get to the fan. On my model (like most) , the cpu fan is directly assembled with the heat sink. First remove the heat sink, then remove the 3 screws from the fan assembly to get to the fins of the exhaust, and the blades. The fan is a silent magnetic (no bearings) type. The blade assembly can be easily pulled, cleaned inside (i used q-tips and alcohol), Blew the dust of the wire coils, and thoroughly clean the fan assembly. (Mine was super bad, the whole exhaust was covered with a 3-4 mm thick layer of dust, that had started to hardened due to heat) Now I know a lot of people suggest using compressed air, but there is no better result than opening the fan completely. Compressed air is good, but is a step that should be used periodically, long before you start having heat issues, because the amount of dust currently inside your 2-3 old laptop, just wont come out with compressed air.
I also removed the older, less effective thermal paste, and applied better quality. Unlike the previous poster, this paste was easily removed in about 1 minute, with just a q-tip, no alcohol.
The results are simply amazing, feels like i have a brand new laptop. I also use K10stat now, to lower the cpu voltage. I lowered the voltage only by 0.05 Volts, and gained 2-3 degree cooler, but i don't think it's such a necessity anymore. Anyways, now my laptop idles at 45-46 degrees, and i cannot hear the fan AT ALL ! The fan use to emit a very high pitch noise, now even when it runs full speed (when i turn on the laptop, the fan always goes full speed for 2 seconds or so) it sounds great. The keyboard is cool, the airflow is great. I was never able to use this laptop on my lap for more than 10 minutes, now i can use it for as long as i want.
I really wish i had gotten off my lazy [bleep] sooner, and clean the fan and change the paste, would of saved my batteries. Shame HP cheaps out on thermal insulation, and i wonder why they don't make the entire fan assembly accessible from outside...