Airport Extreme Limited Internet Access?

[Zompac]

Ok The Airport Extreme has been working fantastic ever since my sister moved in with her laptop http://www.newegg.com/Product/Product.aspx?Item=N82E16834200142

And whenever shes on it, the Apple airport will work just fine, but out of no where the internet will cut out. It will still be connected but it will say "No Internet Access" The problem lies within the Airport Express and Im trying to figure out whats wrong. Only while she is using the internet it will disconnect. Other people in the house use the internet on their computers (My mom's macbook), (A Toshiba Notebook), (Printer Setup) (Iphone), (iPad), but ever sence my sister's DELL laptop connected it's been giving me problems.

http://store.apple.com/us/product/MD031LL/A/AirPort-Extreme?mco=MTY3ODQ5OTY

It's the most recent Airport Extreme

 

[sev]

I don't know if it helps, but youmight want to check the airport extreme's radio settings.

If it's transmitting on 5ghz only it may struggle when something tries to connect with a b/g bandwidth. I had a similar problem.

also check that any other wireless products aren't conflicting with it - wifi routers which haven't had the antennae turned off for instance.

In the airport utility control panel you can force the base station to a particular band so if all your devices are N devices then force it to that.

Also check the dell, as in W7 the wireless manager is sufficient and sometimes dell throw their own rubbish bloatware which sometimes can conflict.