hello everyone please i need urgent help i re-installed vista on my system cos i was having some major problems on it .but not now i cant update windows,i cant install anti virus n install .net, and my vista is activated too, please its fustrating cos i cant really browse wit it cos of fear of virus attack n such, guys i need ur help

i was having problems wit my hp pavilion dv6000 system n so i formatted it n installed another windows vista home premium that came with a system i was using before which was advent ever since then i cant use windows update,install anti virus n vista service pack.