No net at all with Service Pack 2

Archived from groups: microsoft.public.windowsxp.perform_maintain (More info?)

Ok wierd problem here,
I install 2 time sp2 and it does exactly the same thing
After i restart my computer I start the net and after about a min, it stop
working and all my program cant access it. If i deconect the web and i
reconcet it, the same phenomen happen. i disable completly the firewall, i
look at my network propreties, everything is normal and even if the firewall
is desable, i cant access anything until i reconect. So I desinstall the sp2
and i retry about a week later, same thing.
By the way, this appen after i format my computer, with the old windows
before the format i've got the sp2 and its work so ist only after the format
the 2 times i've try that it's not working. Tanks for the help