Windows Vista Can't acess windows/microsoft update

Hi all i was wondering if someone could help me out with a problem i've been having, i recently got my notebook which runs on vista but i can't seem to access the windows or microsoft update servers at all. Also i can't seem to get on windows live messenger (error code 80040154) or download from the microsoft download centre. I'm very frustrated because i had this problem on my desktop which runs on XP professional and i thought it was because of the system but i'm experiencing the same problem on my new notebook. Everything else works fine and dandy i would just like to fix this problem with windows live and microsoft because it is very inconvenient

regards vii