My netbook won't connect to the internet without a wireless adapter.?

I used to have windows XP on my netbook. (its an Acer Aspire One) I did a fresh install of windows 7 ultimate, it works GREAT, except it doesn't connect to the internet wirelessly. It needs a wireless adapter to be able to connect wirelessly where as before, when i had windows XP it did not need it. It's almost like it thinks its a desktop computer. How do i fix it so it will recognize wireless internet again without an adapter? Thank you!