Check with the Acer site or the computer manual whether it has wireless built in and how to switch it on -- if it's recent laptop purchase it will have a wireless adapter already.
If not you can decide on a PCMCIA type wireless adapter, assuming the computer has a slot for it, or USB version of wireless adapter.
it was a new Acer. Acer's help only asked for an up front payment before any information to fix the problem.
We took the Acer back to where we bought and got our money back