connecting to wireless at my college

I bought a inspiron duo so I could use it at school. They have a secure wireless internet and I had them connect me and they told me that I should be able to connect all the time to their internet. Well everytime I shut the computer down and when I turn it back on I cannot connect to their internet. When the guy looked at my laptop he said that the settings keep changing after I shut it down and turn it on. He said it must be something to do with Dells settings and thats why it won't stay connected. Please help if anyone has any ideas or suggestions. Thanks