Can you log into to Hotmail?
What does Hotmail tell you when you send/receive mail?
What browser are you using?
What version of messenger is this?
80046620
Are you sure that error code is correct? Because I get no hits on that one when I google it.
I'm assuming you meant Windows XP and Internet Explorer 5.1?
If so you need to upgrade to IE 6. The new Hotmail and MSN sites don't work very well with IE 5.
XP is also know as Windows NT 5.1, Vista is 6 and so on.
XP shipped with IE 6.