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. Go here: http://www.dell.com/support/drivers/us/en/19/DriversHome/NeedProductSelection , and either enter your service tag (should be on a sticker) or let Dell detect your system type.
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/ [...] e-download , from Saga Lout.
Please satisfy my curiosity: how do you know that this is a driver issue, and not something else?