The driver depends on the particular hardware, and can usually be found on your manufacturer's site if you search under Support for your model. I have looked on the Acer site and not found an "aspire one NAV50," although it does exist. See if you can find any other model number that will fit into the selections on this page: http://us.acer.com/ac/en/US/content/drivers
Alternatively, a very clever member here posted directions on how to identify any hardware that needs a driver. See the second post here: http://www.tomshardware.com/forum/274306-45-video-contr... , from Saga Lout.
Please satisfy my curiosity: how do you know that this is a driver issue as opposed to some other kind of problem?