Dell Studio says limited connectivity

Hello, I have windows vista on my computer. I connect with with a wireless secured network with limited connectivit but with a strong signal. There is a yellow triangle between my pc and the network. I click it to diagnose the problem and it doesn't help. My wife bought her dell the same time I did and it works just great on the same thing. I have a Dell wireless 1397 WLAN mini-card. I have tried to uncheck the protocol version 6 and that didn't work. I tried to enter the ip address manually and that didn't work also. I have no idea what is going on. HELP PLEASE!!