When the screen to reboot comes up, go to
start-run and type CMD
on the black screen type "shutdown -a" and hit enter that will prevent from restat and will give you enough time to fic the problem, it is a blaster worm, you can click on this link http://securityresponse.symantec.com...r/FixBlast.exe , you would have to save it in your desktop and run it..let us know what happen