Windows Messenger Service

From: G H (gileshook_at_bogoff.tredis.fsworld.co.uk)
Date: 01/24/04 

Date: Sat, 24 Jan 2004 20:47:13 -0000

I keep getting these annoying pop-up messages (in grey boxes, and usually
advertising some porn site), despite the fact that my Nortons Firewall is
cranked up to the max! I understand that this is something to do with the
Windows Messenger Service (not to be confused with MSN Messenger - the chat
program).
I know there is a way to disable this on my PC, can anyone tell me how to go
about it, thanks!