Two possibilities immediately come to mind. One, you may have accidentally switched the trackpad off. I think on a Satellite it is the Fn key and F6, but I'm working from memory here. Look at your Function keys and one of them will have some symbol that looks like a mouse and/or a trackpad. You use this, with the Fn key to toggle the trackpad off and on.
The other possibility is that your trackpad may be on the way out. They are, I believe, replaceable if you feel up to it, but the simplest solution is to use a USB connected mouse. As I don't like trackpads, I normally plug a mouse in and switch the pad off if I'm doing anything other than casual work on a laptop.