problem with msn messenger
 

I frequently use msn messenger, and have for a long time, but i recently have a problem with the msn. When I just sign in, msn logs me out every few mintues, but it still looks logged in, its not until i try and message someone that all my msg windows start saying i'm logged out and my contact list turns into the signin screen.
os= windows xp , problem exists with 6.0 / 6.1 / no firewall

I dont have this problem on my second pc,
os= w2k msn ver = 6.1 / no firewall

Does anyone have any ideas as to why this may be?

ok here is a bit more info on the problem

it goes like this :

i sign in , no problem

i'm chatting with a friend
after +- 3 minutes , he says i'm offline , but we can still chat ,
when i click on a name in my contactlist -> msn signs out

get rid of it, download and reinstall it. its probably another stupid worm.

i' have allready tried that
6.0 , 6.1 / dutch / english
still no effect :(