If you're talking about the touchpad, then I'm afraid that no; it's not easily replaced.  The most probable thing that's happened is the microswitch underneath the button has worn/broken.  You not only have to pretty well completely dissassemble the keyboard part of your laptop, but it's a tricky job when you get there.

The best solution is to get an external USB mouse and use that.  It's a bit late to tell you this, but using an external mouse to take most of the wear is the best thing to do anyway...save the touchpad for when you have no other choice.

Reinstall the driver for that touchpad,if the problem remains, then you have to replace it, usually for about $20 in Ebay or somewhere else..