If they say messenger service in the title bar, these have nothing to do
with MSN messenger or Windows messenger. What this is a new way for spammers
to attack your computer and send you pop-up ads. If you receive these ads it
means that your computers netbios ports are wide open to the internet and
this could be a real security problem. What you should do is install a good
firewall that will block the ports the spammers use and stop the ads. A good
place to start is Zone Alarm (
www.zonelabs.com ) for an inbound/outbound
blocking firewall or use the inbound blocking only firewall built in to XP.
If needed configure the XP firewall to block ports 135, 137-139 and 445.
Zone Alarm will block these ports by default.
Use this site to test some of your ports security:
https://grc.com/x/ne.dll?bh0bkyd2
You can disable the messenger service, which is the service the spammers
exploit, but it isn't needed to stop the ads and disabling the service will
not secure your computer from outside attacks or block the open netbios
ports.
Note: If the Messenger service is stopped, messages from the Alerter
service (notifications from your antivirus software, for example) are
not transmitted. If the Messenger service is turned off, any services
that explicitly depend on the Messenger service do not start, and an
error message is logged in the System event log. For this reason,
Microsoft recommends that you install a firewall and configure it to
block NetBIOS and RPC traffic instead of turning off the Messenger
service.
If they don't say messenger service in the title bar, then download and
install a good popup blocker and install and run spybot as well.
http://security.kolla.de/