Look at this, courtesy of Carey Frisch.
There are thousands of nasty computer viruses/worms looking for unprotected
computers. Your computer can be infected within a few milliseconds the
moment
an internet connection is established if your computer is not properly
secured.
Apparently, your computer is now infected with the W32.Blaster.Worm or one
of its variants.
This happened because you have not been using an internet connection
firewall and have
apparently neglected to install the critical updates available at the
Windows Update website.
------------------------------------------------------------------
If your computer is constantly attempting to shutdown
or reboot, quickly go to:
Start > Run and type: CMD , and hit enter.
This opens the Command Prompt window.
Then type: shutdown -a , and hit enter.
This should halt the rebooting problem.
------------------------------------------------------------------
Then immediately turn-on Windows XP's built-in Firewall:
http://www.microsoft.com/security/protect/
Special note if you use AOL:
America Online installs its own connection settings that override
the ones that come with Windows XP. America Online's
connection settings don't include a way to turn on Windows XP's
built-in firewall.
Visit the following web site for instructions on downloading
a FREE firewall program for your computer.
Ref:
http://www.updatexp.com/free.html
What You Should Know About the Blaster Worm and Its Variants
http://www.microsoft.com/security/incident/blast.asp
A tool is available to remove Blaster worm and Nachi worm infections from
computers
that are running Windows 2000 or Windows XP
http://support.microsoft.com/?kbid=833330
A security issue has been identified that could allow an attacker to
remotely compromise a computer running Microsoft Windows and
gain complete control over it. You can help protect your computer
by installing this update from Microsoft.
http://www.microsoft.com/downloads/...6C-C5B6-44AC-9532-3DE40F69C074&displaylang=en