Need help. My internet is sluggish and sometimes after 10 minutes of noninternet use, I can't get back on without restarting my computer. When I called Applecare they had me directly connect the linsys modem ethernet to the computer and it worked lickety-split. But then when I went off the ethernet connection and back to wireless I went back to the same problems. Apple said that there was something wrong with the signal of the Linsys as it is coming to my computer. Any advice?