Aunt Janet was having problems with Windows Messenger Service dialogs. UGH! I can't believe M$ doesn't turn that off by default in XP, at least home addition. There is no reason for it to be on. I turned mine off at the office 2 years ago because it was anoying. The email:

I can take a guess that these are dialogs from the Messenger service. (Not MS Messenger chat program - this is a different "messenger".)

Go to the control panel. (Start Menu -> Settings -> Control Panel)
Open Administrative Tools
Open Services
Find the service Messenger in the list. Double click on it.

If Startup Type: is not disabled, change it to disabled and click OK.

That will turn of the messenger service. This service was used historically to allow network administrators to send messages to users like "I'm going to reboot the server in 10 minutes". Lately spammers and other hackers are using it on computers that are on the internet with no firewall to cause problems.