Please could you give us more information.
I understand that you have a computer with a wireless USB adapter plugged into a USB socket on the computer.
Do you have a wireless router?
Do you have other computers which connect to your wireless network?
Do you have a problem connecting to the wireless network or can you successfully connect to the wireless network but have a problem connecting to the Internet?
Which error message do you get when you try to connect?
If you can connect to the wireless network but not to the Internet, you will be able to access your router's webpage. Go to Internet Explorer and type
http://192.168.1.1 in the address bar.
If you can't do this, do it on another computer connected to the wireless network. Here you can check that there are no restrictions set up, or if necessary you can reset the router.