wireless network slowing me down

When I open my airport (onto a netgear wireless modem/router) my computer slows right down, it takes ages to open programs and save bookmarks in safari. when the airports closed it all works fine. I don't know where to start?

try playing around with the permissions and network settings, it might be reading programs off of a server? That is how it was at my school, the macs were so slow when they were on the server, but if you took it off the network it sped up, because it was reading things from the server. Try that, don't know but lets try to eliminate something.