It is common for notebook computers to acquire dust and/or lint on heat sink surfaces, and yes this could be why your notebook is overheating. It is also possible that a virus is causing the CPU to work more than it should adding to the heat generated. You should, of course, remove any virus from your computer. If you can, check the heat sinks for dust or lint build up. You can usually see them through cooling vents in notebook computers. One thing that I find helps a great deal is using notebook cooler
. You can usually get them for under $30 and most do a good job of keeping a notebook computer much cooler.