Why Wont My Ds Connect To My Nintendo Wifi Usb Connector?

I have a nintendo USB wifi connector and usually my DS connects to it fine, but for some reason it isnt working now. The ds will connect for a few seconds and the little bubble pops up saying a user is connected and then it disconnects again. I have tried taking it out and putting it back in and turning off the firewall but still nothing.
Yesterday my laptop wasnt connecting to the internet and my boyfriend told me it was something to do with a proxy setting or something like that but i have no idea what he meant and what to look for.
Can any one please help?