Rather than being a virus or whatever in a malicious way, it is just plain annoying...
"The Windows "Messenger Service" is being exploited to spray the Internet with unsolicited commercial eMail. The receipt of a single UDP packet can cause a "Messenger Service" dialog to pop-up on the user's screen. It is possible for the sender to "spoof" (falsify) the packet's "Source IP", making these packets impossible to trace back to their origin. If our experience with eMail Spam is any model, we can expect to see a lot more of this in the future."
Windows XP Home
1. Click Start-> Settings -> Control Panel
2. Click Performance and Maintenance
3. Click Administrative Tools
4. Double-click Services
5. Scroll down and highlight Messenger
6. Right-click the highlighted line and choose Properties
7. Click the STOP button
8. Select Disable or Manual in the Startup Type scroll bar
9. Click OK
Method 2: visit GRC*|*Shoot The Messenger**
and download respective software
Method 3: Unfailing; TREND MICRO-SYSTEMS "Sysclean
Have you tried Trend MicroSystem's Sysclean...can be run in windows, withing DOS window, or in safe mode with DOS windows. Also download the latest >>>pattern file for Sysclean to use. Setup c:\sysclean, into which you will insert a copy of the anti-virus pattern.
Run the pattern by opening the folder
1. Trend Micro Damage Cleanup Engine / Template
2. Trend Micro Pattern Files
Your engine is the DOS looking icon "sysclean.com." I'd put a shortcut on my desktop for emergencies.
The Virus pattern file protects customers against viruses.
The Virus cleanup template automatically removes the virus from the customer's system.
* Virus Pattern File (Controlled Pattern Release) - 5.208.02
When you have an inkling that you have been invaded by a virus, close all programs as best you an, then startup sysclean...
A DOS window will open, follow the instructions. You will note hundreds of codes installing...ignore that...The whole process may take an hour or so, so be ready for it.
I run sysclean once a month for good measure.