First off, never trust a company that exploits a technology to advertise that they can prevent it. Second, yes you can stop these. We ran the tip two months ago, but it seems I'm getting this question three or four times a day, so here's your "summer re-run".

You are probably familiar with Windows (a/k/a MSN) Messenger which is used for Instant Messaging. There is another program called Messenger that is used in networks to transmit and send alerter service messages between clients and servers.

Even though you'll never use it, unless you are on a network, by default it is turned on, causing an open hole in your XP firewall for pop-up advertising to get through. Here's what to do if you want to stop Messenger...

Go to Control Panel / Administrative Tools / Services (or Start / Run and type in "services.msc"). This will bring up a long list of Windows services that are running or available on your system.

Find "Messenger" and double click to open the Properties box. In the "Startup Type" field, change the setting to "Manual". You could choose "Disable", but if any services depend on Messenger they will fail to start, so you're better off playing it safe.

Click OK to save changes.