Here is the download site for Acer divers.
http://support.acer-euro.com/drivers/downloads .html
Put in the model of your laptop.
It may then ask you for the version of Windows you are running.
It may then offer a list of drivers: sound graphics etc.
Download the ones you need.
Or it may offer one large file that contains all the drivers.
If so download it and then follow any instructions for install.
BTW, did the laptop not come with a recovery CD ?
Most laptops do, and if you use the recovery CD it normally installs all the drivers for you automatically.