A shot of compressed air does wonders for cleaning pet hair and dust out of the touchpad sensors. If you remove the keyboard you'll get an even better shot. Be very careful when you remove the keyboard! Find your computer manufacturer's instructions and follow them carefully. The manual that came with your computer should have instructions on how to do this. If you don't have the manual, you can usually find it online at your computer manufacturer's webpage.
If that doesn't work, try reconfiguring your touchpad's driver. Try the various options in Control Panel --> Mouse applet.
Also, you can buy a usb mouse that will plug into any of your laptop's usb ports.
