ISP says SP2 but W Update doesn't work either

Since getting new DSL service with Qwest and MSN, I have been having
problems with email. That seems to have resolved itself somehow, but I
can't log into my 50megs website. The user name for the login includes
the domain name. When I try to log in, I get site not found. The weird
part is that other people (with other ISP's) can log into my account. I
didn't really understand what the guy at 50megs was saying but he seemed
to be indicating that the lookup of the account name during login wasn't
local but used DNS and thought my ISP's DNS was out of date. Qwest says
that isn't it, thinks the problem is with 50megs but tells me to get SP2
which I would except that Windows Update doesn't work. They are sorry,
but the requested page cannot be displayed. I am wondering if the
problem with WU is the same one I am trying to fix or is this something
that happens frequently? I tried all the things suggested on the page
but to no avail. All my shields are down and my system is totally naked
but it still doesn't work.