Windows Xp only connecting to one network! HELP

Hi, I recently purchased a netbook and have been having problems with connecting to my wireless network. When I first purchased the laptop my internet was down so I asked my neighbor if I could use his wifi and he said that would be fine. Now that my internet is back up I cant connect to my wireless network, I have been trying all day. When I click my network and type in the password all that happens is ''aquiring network address'' for about 30 seconds and then it wont connect, and a red x appears in the bottom right of the toolbar.

Acer aspire one
Network adapter: Atheros AR5007EG


HELP