Hey, im new to ubuntu and i only got it a few days ago (Ubuntu 10.10)

At first the wifi worked, then after the install it didnt work, so i plugged the LAN cable in and downloaded the updates it recommended. then today it asked me to install some more updates, i did and when i rebooted my laptop (Samsung N130) The wifi doesn't work, it asks for the wireless key, i enter it correctly but it never accepts it it trys to reach the rooter and fails

Help please??