The type of modem depends on your Internet connection, be it DSL, cable, or dial-up. The modem should have wireless capabilities or you will need a wireless router.
Depends on what kind of internet connection you are looking at. Its really independent of your computer. DSL/Cable are popular choices and usually the service provider (like AT&T or RoadRunner) will give you a modem.
Modem is required for internet access. Generally internet providers also provide the modem. Therefore, you need not to worry about the modem selection. Let the service provider take care of it.
I would search online.. typing your model including download modem (or something similar) when it lead you to the acer website they should have your model and correct modem for it.
the modem should be suitable to our computer then only the internet connection will work. the modem will be provided by the internet service provider so that they know the make of the modem which will be suitable for the computer.