There are many potential reasons your laptop might be hot, but the most likely one is that the fan isn't working properly. If the fan is constantly loud and your laptop is always warm to the touch, then it's likely that the fan is not working as efficiently as it could be. In some cases, a dirty fan can also cause overheating. Opened software or files on your computer may also cause heat buildup, and if you're using a laptop on an open plane or in a large public area, this heat will be amplified.