Eratic crursor behaviour selecting difficult

I have a macbook 2 ghz Intel Core 2 duo, model A1181, 13 inch. After being on for a couple of hours, the cursor starts acting erratically. I can't finish typing text and moving the cursor without pushing the track pad, things are randomly selected, windows close and it is impossible to navigate. Is this a track pad issue? Can I replace the track pad myself? Is the procedure similar to your video for the Pro? I had to type this message using another computer, moving the file to the Macbook, copying and pasting into this box. Thanks.