Just starting out using Linux Ubuntu

I got a Acer Travelmate 4200 laptop which wasn't in use so I thought I'd install Ubuntu onto it and have abit of play and see how it all works

It works great and all only problem I am having is the wireless stops working when I try to download anything like an update or just a file a few megs in size it just stops working but the connection still shows as being connected but it won't load pages and the download just stops downloading. Only way to get it going again is to disconnect and connect again and the same thing happens again when I try to download something.. normal browsing works fine just when I download something it stops working

I am very new to Linux OS so any help would be appreciated