There are several kinds of popups -
* browser popups (which you can stop with many things, such as
http://toolbar.google.com)
* messenger service popups (which mean you haven't got a firewall installed
or properly configured- see below)
* popups due to spyware/adware - find & install AdAware & Spybot, update
them, and run full scans
For Messenger Service popups:
'Messenger spam', is not in itself harmful, but is symptomatic of a larger
problem - your computer has ports open from the Internet.
You can disable the Messenger service, but that is unwise as a solution as
you'll still have the underlying problem that caused you to get the messages
in the first place - consider the messages a useful warning that you have no
protection from the Internet. This is all too important now, given the
recent rash of RPC worms....
For a standalone machine, see
www.sygate.com for a free personal firewall,
or if using Windows XP, you can enable the built-in internet connection
firewall (ICF).
See
http://securityadmin.info/faq.htm for more info. Also,
http://www.mvps.org/winhelp2002/nopopups.htm is a good resource - although
for browser popups, you might want to consider
http://toolbar.google.com -
it works like a champ and is also handy for searching.