Shoutbox

Hi guys.I really need help
My MSN is acting weird.
I talk to somebody,then it sudenly stops delivering any messages to my contacts.it sends them back 'following msgs could not be delivered' ..
When I restart it,it helps sometimes,but in a few minutes it stops delivering msgs again.What helps is when the person starts talking first,then my messages go through just fine.
I thought it might be caused by Windows live mail beta,as I signed to it just a few days ago.I opted out of it,but MSN keeps acting weird.
I also tried reinstalling MSN.it didnt help either

I thought its a virus,but when I scanned with Kaspersky,it didnt find anything.
I also dont have firewalls....so I have no idea what it is at all.
help please!