Hi Vistamire,
it looks like the problem is that something is stopping Vista from reaching the Windows Update site.
Lets check your HOSTS file and make sure it is clean and there are no bogus entries for any windows update sites.
Check out this link
Changing your hosts file in Vista and tell me what the contents of your HOSTS file is.
The next thing to try is check your PC for Malware as some malware try to stop the PC from getting updated. Try one of the many online scanners and see if they show up anything.
10 Online Virus & Malware Scanners
let us know how you get on,
regards
Steve