|Download the touchpad driver for your model from Acer's website, then install it: http://support.acer.com/us/en/produ...|
You will need to know the full model number because there are at least a dozen different Aspire One models. Look underneath for full model number.
The website URL above is for United States.
If that is not correct for you, click "United States" at bottom-left to change country.