windows live messenger(offline)

hi guys i am new to this section.anyway i am having alot of problems first one is windows live messenger it shows window opens but when i sign automatically i am seeing windows live messenger (offline) right next to it it shows like this windows live messenger(offline) i cant get it to show online, i cant sign in at all. second one is when i go to internet explorer to go to msn homepage..i get a message saying http 404 not found.then i also get there is a problem with the websites security certificate for msn there is something going on here i am also getting when i open a page small white box window open says MTxr could not create file mapping object (5) also thats creating a problem for me what do i need to do to clear this up and to get windows live messenger(offline) fixed to be online not showing offline... then how do i fix the other things as well i am trying to get online asap