Internet connection problem.....?

for like 2 weeks i am having some weird internet connection problem. only internet explorar can connect to internet. my limewire, bit torrent and itunes store is not woking at all. also, in in ie, when i am trying to search anything it is showing page cann't show. but after refresh the page i can see it . i am using AT&T dsl and i have norton internet security 2006. but i cann't open norton. pls help me....................