Chances are you have quit a bit of dust and dirt inside the computer, especially near the fans. You can use a can of compressed air to blow some of it out, or if you feel comfortable doing it, you could take the laptop apart (some are harder than others) and clean everything out that way. If the computer is getting hot, then the CPU is probably slowing itself down to keep from overheating. Too much dust clogging the fans and being on the heat sinks can definitely cause it to get very hot.
If you do get a new laptop, most people agree the Toshiba laptops are the best right now.